Bedwarmer

Part of speech: noun

Definitions

1. A companion or object that offers heat and comfort in a sleeping area serves to alleviate cold temperatures during rest
2. A device used to make a bed warm before sleeping ; someone who provides warmth in a bed by sharing body heat or presence
3. An object designed to heat bedding for comfort during cold times ; a person who occupies a bed to keep it warm for another

Etymology: A bedwarmer was once a brass or copper pan with a long handle, filled with hot embers and slid between the sheets to take the chill off a cold mattress before anyone climbed in. The pan was the heating device; the sense of the word that refers to a person is the later extension, meaning someone who occupies a bed to keep it warm for another. The word is a plain compound of "bed" and "warmer", the second part being an agent noun from "warm", so its meaning is transparent from its parts. Its literal sense has nothing to do with people: a warmer is any device that warms, and the bed is where it was used. The person sense is the surprising turn. Someone who warms a bed for another, often a servant sent ahead of a master or mistress, took the job of the pan and became the thing being warmed up for. The two senses sit side by side, the object and the human stand-in, and the compound holds both.