I can’t find a pause button in Terraria, is there one? If I press the escape key, it just brings up my inventory – I tried pressing different keys, but none of them seem to do anything.
You can Alt-Tab out of the window, or simply click out of it if playing in windowed mode, and it will pause gameplay. It’s hackish, but it does pause (you can also do this during loading, and it will keep loading).
As James has pointed out, this is single-player only. There is currently (and I doubt there ever will be) no multiplayer pause.