A vary strangely named environment for interactive

theorem proving, somewhat like

HOL. COQ is French for

rooster.
From the COQ web page:

Developed in the LogiCal project, The Coq tool is a proof assistant which:

Coq is written in the Objective Caml language and uses the Camlp4 Pre-processor-pretty-printer for Objective Caml.

The current version of Coq is the 6.3.1. It is currently available for Unix and Windows 95/98/NT systems .