/T/ 1. [from LISP terminology for `true'] Yes. Used in reply to a question (particularly one asked using the `-P' convention). In LISP, the constant T means `true', among other things. Some hackers use `T' and `NIL' instead of `Yes' and `No' almost reflexively. This sometimes causes misunderstandings. When a waiter or flight attendant asks whether a hacker wants coffee, he may well respond `T', meaning that he wants coffee; but of course he will be brought a cup of tea instead. As it happens, most hackers (particularly those who frequent Chinese restaurants) like tea at least as well as coffee --- so it is not that big a problem. 2. See time T (also since time T equals minus infinity). 3. [techspeak] In transaction-processing circles, an abbreviation for the noun `transaction'. 4. [Purdue] Alternate spelling of tee. 5. A dialect of LISP developed at Yale.