(1) Acronym -- The Rest of Canada. Pronounced "tea-rock".
(2) TROC is a very regional thing:
(a) If you live in the Maritimes
, then it is anything west of Quebec;
(b) If you live in Quebec
, it is English-speaking Canada
(c) If you live in The GTA
; then it is anything past the Greenbelt.
(d) If you live in Windsor
, Ontario; then it is anything outside of Essex County, Ontario.