Arcade is a lightweight and secure expression language used in ArcGIS products and APIs. Arcade expressions are commonly used to calculate or format field values for data-driven visualizations, labels, and popups. The expressions work against data stored in data services.
Like other expression languages, Arcade can perform mathematical calculations and evaluate logical statements. It was designed specifically for creating custom visualizations, popups, and labeling expressions, allowing users to write, share, and execute expressions in ArcGIS Pro, ArcGIS Online, ArcGIS Maps SDKs, and ArcGIS API for Python.
What makes Arcade particularly unique to other expression and scripting languages is its inclusion of geometry functions. These geometry operations allow you to calculate areas and lengths, test topological relationships, and perform simple overlay operations.