1. To become hot from the outside to the center. We recommend using a meat thermometer to make sure that the chicken has heated through in the oven.
2. To cause someone or something to be hot throughout. In this usage, a noun or pronoun is used between "heat" and "through." You've got to make sure you heat the leftovers through before you eat them, or you could make yourself really sick. We came in out of the snow and stood by the roaring fire, letting it heat us through.
3. slang To cause someone to be filled with sexual desire. In this usage, a noun or pronoun is used between "heat" and "through." His touch on the small of my back instantly heated me through.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.