Three heat treatments that work together in sequence — not three interchangeable ways to "heat-treat" a metal.
It's easy to lump "heat treatment" into one vague bucket — heat the metal, do something to it, cool it down, get a better part. In practice, annealing, quenching, and tempering are three specific, well-defined operations that share almost nothing except a furnace. Two of them — quench and temper — are routinely applied back-to-back to the very same part, in a fixed order, because neither one alone gets you where you need to be. The third, annealing, isn't a step in that sequence at all: it's a different process, aimed at a different goal, usually applied at a different point in a part's life. Mixing these three up isn't just a vocabulary problem — it's the kind of mistake that leaves a real part dangerously brittle.