# Overview
The definition feature allows users to declare constructions (such as Alarms, Events, Functions, and Variables) and subsequent mapping of these definitions within model definitions, type definitions, and object model extensions.
Definition APIs contain four categories:
String Length Limit
All properties, variables, and attributes that have a string
data type cannot exceed a length of 64135 characters when part of a PUT
,
POST
, or PATCH
operation payload.