time T: /ti:m T/ n. 1. An unspecified but usually well-understood time,

:time T: /ti:m T/ n. 1. An unspecified but usually well-understood
time, often used in conjunction with a later time T+1.
"We'll meet on campus at time T or at Louie's at
time T+1" means, in the context of going out for dinner:
"We can meet on campus and go to Louie's, or we can meet at Louie's
itself a bit later." (Louie's was a Chinese restaurant in Palo Alto
that was a favorite with hackers.) Had the number 30 been used instead
of the number 1, it would have implied that the travel time from
campus to Louie's is 30 minutes; whatever time T is (and
that hasn't been decided on yet), you can meet half an hour later at
Louie's than you could on campus and end up eating at the same time.
See also {since time T equals minus infinity}.
-- The AI Hackers Dictionary