What app name availability actually means
App name availability is the question of whether the name you want is already used by a live app, or by something close enough to cause confusion, in the stores and markets you plan to launch in. It is not a single global yes or no. The App Store treats every country as its own catalog, so a name can be completely free in the United States and already claimed in Germany, Japan, or Brazil. Google Play adds another separate layer, with its own listings and its own crowded keywords.
Because of that, the real answer is always regional and always about degree. A name might be clear in nine of your ten target markets, share an exact match in one, and sit next to a handful of similar names in a few more. Understanding that shape, rather than a flat available or taken, is what lets you make a confident naming decision instead of a hopeful guess.