Skip to content


Each item in the glossary is also a Tooltip. The word or phrase is repeated in parentheses to assist those using Google Translate.

When Google Translate is selected:

  • Tooltips, indicated by dashed underline, continue to be shown in English
  • On the Glossary page
    • The first instance (in bold) remains in English
    • The second instance (in parentheses) is translated to your selected language

Actions  (Actions): a custom application for the GitHub Actions platform that performs a complex but frequently repeated task; specifically used to build Loop from a browser

Activated  (Activated): for Omnipod: time at which insulin was injected into pod and 2 beeps were heard

Anchor Links  (Anchor Links): any header on a LoopDocs page can be used as a link, tap on the paragraph symbol at the end of the header to view the link in the URL

API_SECRET  (API_SECRET): password (min 12 characters) needed to access Nightscout Site

API  (API): Application Programming Interface

APN  (APN): Apple Push Notification service, required for issuing remote command via Nightscout

App Group  (App Group): a unique identifier that Apple users for a given app, yours has your TEAMID embedded in it,

Automatic Bolus  (Automatic Bolus): provide a fraction of the recommended insulin automatically with each updated CGM reading (default 40%)

BAGE  (BAGE): pump battery age on Nightscout site

Big Sur  (Big Sur): older version for operating system for Mac, macOS 11.x

BLE  (BLE): Bluetooth low energy, used for communication by phones, CGM and some pumps

Build Select Script  (Build Select Script): by running a command in your terminal, this menu-driven tool assists in building Loop

branch  (branch): version of code within a single repository or workspace repository

CAGE  (CAGE): cannula (or pump site) age on Nightscout site

carthage  (carthage): a program that used to be required to build Loop - no longer needed

Catalina  (Catalina): older version for operating system for Mac, macOS 10.x

Certificate  (Certificate): Apple certificate is used to sign your iOS or Mac apps - tied to but different from your permanent Developer ID

CGM  (CGM): continuous glucose monitor, wearable medical device that measures and reports glucose in interstitial fluid

Closed Loop  (Closed Loop): Loop will make automated adjustments of insulin delivery using predictions based off user entries, settings, IOB and COB

Open Loop  (Open Loop): Loop will not make automated adjustments of insulin delivery but predictions and recommendation features are available

clone  (clone): create a copy of a repository on your computer including revision history and ability to update using git commands

COB  (COB): Carbs on Board, affects automated insulin delivery: the g of carbohydrates that Loop expects to be absorbed and uses for glucose prediction

commit  (commit): a formal change to files in a repository; each commit has an alphanumeric identifier (SHA-1)

Config Vars  (Config Vars): configuration parameters for a Nightscout Site

Correction Factor  (Correction Factor): how many points your blood sugar will drop for each unit of insulin; Loop calls this Insulin Sensitivity Factor (ISF)

Correction Range  (Correction Range): Loop recommends changes to basal and / or bolus to bring glucose predictions into this range

CR  (CR): Carb Ratio; how many grams of carbs are covered by one unit of rapid-acting insulin

Delivery Limits  (Delivery Limits): max bolus and max basal rates allowed by your therapy settings

Developer Mode  (Developer Mode): Extra security for iOS 16 and newer; this must be turned on to allow an app built from Xcode directly to the phone to run on a phone or watch

DIA  (DIA): Duration of Insulin Action, the full time insulin is active including a long, low-level tail

DIY  (DIY): Do it yourself, a common acronym for the open-source software community (and the maker community)

Dosing Strategy  (Dosing Strategy): chosen method for increased insulin dosing: (1) High Temp Basal or (2) Automatic Bolus with scheduled basal

dynos  (dynos): used to reboot a Nightscout Site

EmaLink  (EmaLink): radio-frequency device Loop uses to control Eros pods (aka. Gen 3) and older Medtronic pumps

EGP  (EGP): Endogenous Glucose Production: glucose produced by the body from its reserves (mainly glycogen in the liver)

Event History  (Event History): record of pump events (bolus or temp basal) reported and used by Loop

Expiration Date  (Expiration Date): your Loop app has a finite life, the app warns you starting 3 weeks before the expiration date

fastlane  (fastlane): used as part of the github Build Action method that enables building Loop without a Mac computer or Xcode

Finder  (Finder): graphical folder and file display on Mac

fork  (fork): a copy of code in a github repository other than the original

GBPA  (GBPA): Glucose Based Partial Application: modification to Automatic Bolus Dosing Strategy

GIF  (GIF): Graphics Interchange Format (GIF) can be used for small animations and low-resolution video clips

git  (git): a tool for version control

GitHub  (GitHub): an online service for storing repositories, accessible from a browser  ( an online service for storing repositories, accessible from a browser

GitHub Personal Access Token  (GitHub Personal Access Token): used to enable Browser Build of Loop

Glucose Chart  (Glucose Chart): Display of measured and predicted glucose values

Glucose Safety Limit  (Glucose Safety Limit): Loop will not suggest insulin delivery when glucose prediction (in next 3 hours) goes below this limit; in Loop 2 this was called Suspend Threshold

GMT  (GMT): Greenwich Mean Time is mean (average) solar time at 0 degrees longitude, see UTC

Guardrails  (Guardrails): limits in the code for user selected settings, recommended and absolute limits are provided

Hamburger Menu  (Hamburger Menu): three parallel lines that, when tapped, open a new menu

HUD  (HUD): Heads-Up Display at top of Loop main screen, phone in portrait mode

ICE  (ICE): Insulin Counteraction Effect - Loop models the expected glucose change based on carbs entered, absorption time and your settings; and adjusts based on measured glucose

Identifiers  (Identifiers): names of modules found on your Apple Developer Identifiers page that are required for GitHub build method

IOB  (IOB): Insulin on Board, affects automated insulin delivery: the current active insulin (above or below the basal rate) that Loop calculates and uses for glucose prediction

iOS  (iOS): operating system used by Apple Mobile devices (iPhone, iPod, iPad)

IRC  (IRC): Integral Retrospective Correction: Optional alternative to Retrospective Correction that integrates glucose deviations over a longer time frame

ISF  (ISF): Insulin Sensitivity Factor; how many points your blood sugar will drop for each unit of insulin; sometimes called Correction Factor

Issue  (Issue): On github - a formal method to report a problem, either code behavior or documentation

JSON  (JSON): JavaScript Object Notation; a standard data interchange format that is text-based and human readable

macOS  (macOS): operating system for Mac computer

Lock your Phone  (Lock your Phone): click the button on the side of the phone to lock it - prevent accidental touch, i.e., accidental Loop command

Loop 3  (Loop 3): Latest release with major updates

Loop Cycle  (Loop Cycle): typically 5 minutes: new CGM reading, prediction update, pump update and, if in Closed Loop, dosing update if needed

Loop Caregiver  (Loop Caregiver): An app you can build to provide remote commands to Loop using Nightscout

Loop Follow  (Loop Follow): An app you can build to provide extra alarms and views of important information - can use Dexcom Share or Nightscout to include Loop information

Loop  (Loop): With a capital L, Loop is one of several do-it-yourself artifical pancreas systems

Match-Secrets  (Match-Secrets): a private repository you must create in your github account, stores keys required to build with github Build Actions

MTB  (MTB): Manual Temp Basal: user initiated temporary basal, Omnipod Common feature

MDT  (MDT): common abbreviation for Medtronic pumps

modal  (modal): message or alert appearing in front of app that must be acknowledged to return to app

Modules  (Modules): the Loop code uses a number of modules to handle different components of the entire app

Monterey  (Monterey): operating system for Mac, macOS 12.x

Nightscout  (Nightscout): a personal website used to view your glucose and diabetes management data, Loop can upload to Nightscout

Onboarding  (Onboarding): familiarize new, and existing, Loop users with settings in Loop 3 and ensure the Therapy Settings are all entered and are within safety guardrails

Omnipod  (Omnipod): Insulet tubeless insulin pump; Loop supports Eros (with RileyLink) and DASH. Eros is also known as Classic, UST400, and System.

OrangeLink  (OrangeLink): radio-frequency device Loop uses to control Eros pods (aka. Gen 3) and older Medtronic pumps

OTP  (OTP): one-time password, this is used to enable caregivers to securely execute remote commands to a Looper's phone

Override  (Override): a modification to Loop settings that can change the correction range, the sensitivity (basal, ISF and CR) or both

Package Dependencies  (Package Dependencies): packages that must be downloaded by Xcode (once) to build the app after downloading the LoopWorkspace to your computer

pill  (pill): on Nightscout, small boxes with information, tap for extra details

PR  (PR): Pull Request - a formal method to request changes to a repository

prebolus  (prebolus): take some or all of a meal bolus before eating

Pre-Meal Range  (Pre-Meal Range): modify the correction range for up to one hour by tapping on an icon in the toolbar

Provisioning Profile  (Provisioning Profile): associates your app with your Developer ID and limits app lifetime to 1 year (paid) or 1 week (free)

Pull Request  (Pull Request): formal method to request changes to a repository

QR  (QR): a machine-readable code consisting of an array of black and white squares

Quit the Loop App  (Quit the Loop App): quit out of the app - different from closing the app - typically you swipe up in the app switcher

repository  (repository): contains project files and each file's revision history

RileyLink  (RileyLink): radio-frequency device Loop uses to control Eros pods (aka. Gen 3) and older Medtronic pumps

RC  (RC): Retrospective Correction: part of the Loop model that considers actual glucose compared to earlier predictions

SAGE  (SAGE): sensor age on Nightscout site

Secrets  (Secrets): a method to securely embed personal information into your fork of LoopWorkspace to enable GitHub to have access required to build Loop

TEAMID  (TEAMID): One of 6 Secrets: Apple Developer account member number

FASTLANE_ISSUER_ID  (FASTLANE_ISSUER_ID): One of 6 Secrets: the issuer ID is associated with your Apple Developer ID and never changes

FASTLANE_KEY_ID  (FASTLANE_KEY_ID): One of 6 Secrets: Key ID provided when you create an API key in App Store Connect; it is associated with the FASTLANE_KEY

FASTLANE_KEY  (FASTLANE_KEY): One of 6 Secrets: Really long key (several lines); it and FASTLANE_KEY_ID are generated together

GH_PAT  (GH_PAT): One of 6 Secrets: Generated with your GitHub account; set it to never expire

MATCH_PASSWORD  (MATCH_PASSWORD): One of 6 Secrets: password you make up but must save and cannot change without deleting the Match-Secrets repository

SHA-1  (SHA-1): Secure Hash Algorithm 1; used to generate an alphanumeric code for commits in git (github)

Sign Targets  (Sign Targets): associate a Developer ID with an app; must sign all targets for a given app

submodules  (submodules): for Loop, submodules are repositories defined in the Workspace repository that are required to build the app

Table of Contents  (Table of Contents): (TOC) is the list of level 2 and 3 headers on a given page; the title at the top of the page is a level 1 header

Temp Basal Only  (Temp Basal Only): provide the recommended insulin automatically using an increase in temp basal over half an hour (limited by max temp basal)

Temp Basal  (Temp Basal): modify the scheduled basal rate for a pump

Terminal  (Terminal): interface for entering commands to the computer

TestFlight  (TestFlight): a method to distribute apps without direct connection

Therapy Settings  (Therapy Settings): Basal Rates, ISF, CR, correction and safety ranges and delivery limits

Tokens  (Tokens): on Nightscout, configure access permissions using tokens

Tooltip  (Tooltip): brief definitions provided for important terms and abbreviations on the website

URL  (URL): website address (Uniform Resource Locator)

UTC  (UTC): Coordinated Universal Time is a time standard for civil time and time zones worldwide

Ventura  (Ventura): operating system for Mac, macOS 13.x

watchOS  (watchOS): Apple watch operating system; must be compatible with phone iOS

workflow  (workflow): a set of instructions to GitHub to perform an action; the instruction files are found in the .github/workflows folder of the repository

Workspace  (Workspace): a grouping of several repositories into a complete package

Xcode Preferences  (Xcode Preferences): older name for Xcode Settings

Xcode Settings  (Xcode Settings): as of Xcode 14, Xcode menu uses Settings instead of Preferences

Xcode  (Xcode): program used to build an app