Welcome to the Airtable community!
While the word “app” can mean different things in Airtable, usually it means an individual component in the “apps” dashboard on the right side panel. These apps include Page Designer, Chart, Base Schema, Dedupe, and other useful tools. Bases in free workspaces can install one of these apps. Bases in legacy Pro workspaces can have unlimited apps. Bases in new Pro workspaces can have 10 apps.