1. Variety, type, kind. "DDT commands come in two flavors." "These lights come in two flavors, big red ones and small green ones." See vanilla.
2. The attribute that causes something to be flavorful. Usually used in the phrase "yields additional flavor". "This convention yields additional flavor by allowing one to print text either right-side-up or upside-down." See vanilla.
This usage was certainly reinforced by the terminology of quantum chromodynamics, in which quarks (the constituents of, e.g. protons) come in six flavors (up, down, strange, charm, top, bottom) and three colours (red, blue, green), however, hackish use of "flavor" at MIT predated QCD.
3. The term for "class" (in the object-oriented sense) in the LISP Machine Flavors system. Though the Flavors design has been superseded (notably by the Common LISP CLOS facility), the term "flavor" is still used as a general synonym for "class" by some Lisp hackers.
(01 Nov 1994)