Knockers

Part of speech: noun, verb

Definitions

1. A pair of decorative or functional devices typically mounted on a door for announcing a visitor's presence by tapping or banging against the surface
2. A term that may colloquially refer to breasts in a light-hearted or exaggerated manner, often used in informal contexts
3. An object, often in a playful context, that prompts interaction or serves as an embellishment on a doorway, while also having connotations in slang regarding female anatomy

Etymology: "Knockers" for breasts is a slang coinage from the 1940s, which is a surprise given how neatly it fits the older sense of the verb "knock." The word is built from "knock" plus the agentive suffix "-er," so it literally names something that knocks. The idea behind the joke is that breasts are the parts that bounce and swing, so the slang borrows the thumping, rapping action of a knock and applies it to the body. The noun "knocker" was already a familiar English word long before this sense appeared. It has long meant a device for rapping on a door, the metal ring or hammer fixed to a house entrance, and that older sense is what the slang draws on. Because a door knocker is a simple, everyday object, the wordplay was easy to recognize, and the slang term has stayed in use ever since.