IPA: //ˈpleɪnər//
KK: /ˈpleɪnər/
A tool or machine used to make surfaces smooth, especially for wood or metal, by removing thin layers of material.
The carpenter used a planer to create a perfectly flat surface on the wooden board.
Planer → The word 'planer' is derived from 'plane' (from Old French *plane*, meaning flat or level) and the suffix '-er' (meaning a person who). A planer is a person or tool that makes surfaces flat or level.
Think of someone or something that makes surfaces 'flat' ('plane') — the '-er' indicates a person or tool that performs this action.