The following definitions are used here:

Term Definition
3rd Party Dependency Here: (usually open source) 3rd party software artifacts, used by an application (e.g. libraries, Maven artifacts).
API Here: Web-based interface (e.g. a RESTful service)
Application Here: Synonym for web-based application or service.
Change Change to an application in production.
Criticality Here: Either synonym for business criticality or criticality of vulnerability.
Confidential Data Data, which consists of (1) confidential information (e.g. trademarks, sensible business logic, passwords, or personal data), (2) is explicitly declared as those, or (3) is only accessible by a restricted number of people.
Critical Application Here: Business critical application
Dependency Repository System that manages 3rd party dependencies (e.g. libraries, Maven artifacts). A dependency repository is often part of a general software repository system such as Nexus or Artifactory.
External Application A web-based application that is accessible from the outside of the organization (e.g. via the Internet).
Internal Code Source or program code that is not confidential and not public (standard).
Internal Application A web-based application that is only accessible from the inside of the organization (e.g. intranet application).
IT Security Function Here responsible IT security function as defined in Roles. Note that this is intended as a placeholder for the respective role name in your organization (e.g. security officer, architect, or engineer).
Risk Class Basically the risk class adds the exposure as an additional dimension to the critical factor resulting in its risk. Thereby the risk class >= [HIGH] covers not only (business) critical applications and services but also those with medium criticality that are, however, exposed to the Internet. See Risk Classes.
Security Champion (SC) See Roles
Sensitive Code Source or program code that contains confidential information such as sensitive business logic
Service Here: Synonym for a (business) application that can contain one or more ->APIs
Source Code Repository System where custom code is stored (e.g. Git).
Web Application Here: A software program (UI, service API, or combination of them) that is accessible via HTTP(s) protocol and fulfills a particular business case.