The Collaborative International Dictionary of English v.0.48:

Uni- \U"ni-\ [L. unus one. See One.]
   A prefix signifying one, once; as in uniaxial, unicellular.
   [1913 Webster] Uniat

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

UNI

   1.  Ente Nazionale Italiano di Unificazione.

   2.  User Network Interface.

   (1999-02-01)