1. True. A Lisp compiler by Johnathan A. Rees in 1982 at Yale University. T has static scope and is a near-superset of Scheme. Unix source is available. T is written in itself and compiles to efficient native code. Used as the basis for the Yale Haskell system. Maintained by David Kranz <firstname.lastname@example.org>.
["The T Manual", Johnathan A. Rees <email@example.com> et al, Yale U, 1984].
2. A functional language.
["T: A Simple Reduction Language Based on Combinatory Term Rewriting", Ida et al, Proc of Prog Future Generation Computers, 1988].
3. (lower case) The Lisp atom used to represent "true", among other things. "false" is represented using the same atom as an empty list, nil. This overloading of the basic constants of the language helps to make Lisp write-only code.
4. In transaction-processing circles, an abbreviation for "transaction".
5. (Purdue) An alternative spelling of "tee".