IPA: /ˈtuːθbrʌʃ/
KK: /ˈtuːθbrʌʃ/
A small brush with a handle used for cleaning teeth.
I brush my teeth every morning with my toothbrush.
Toothbrush → It is formed from "tooth" (from Old English *tōþ*, meaning the hard structure in the mouth used for biting and chewing) and "brush" (from Old French *brosse*, meaning a tool with bristles used for cleaning). The word "toothbrush" refers to a tool used for cleaning the teeth.
Think of a 'tool' ('brush') used for cleaning your 'teeth' ('tooth') — that's what a toothbrush is for.