That is
'that is' is the definition.
('that is' in Latin)
This is all the clue.
(Other definitions for id est that I've seen before include "Ie, in full" , "In other words" , "I mean to say!" , "That is to say (Latin)" , "Namely" .)
'that is' is the definition.
('that is' in Latin)
This is the entire clue.
(Another definition for idest that I've seen is " That is".)