The Collaborative International Dictionary of English v.0.48:

Tac \Tac\, n. [Cf. Tack, n., 4.] (O. Eng. Law)
   A kind of customary payment by a tenant; -- a word used in
   old records. --Cowell. --Burrill.
   [1913 Webster] Tacamahac

The Free On-line Dictionary of Computing (19 January 2023):

TAC

   1. Translator Assembler-Compiler.  For Philco 2000.

   2. Terminal Access Controller.