Ergonomic describes a tool, chair, keyboard, or workspace that has been shaped so a person’s body can work with less pain and less wasted movement. An ergonomic chair supports the back; an ergonomic mouse tries not to twist the wrist. The word is at home in offices, product boxes, and health-and-safety talk. It became common only in the last few generations; it still sounds a bit technical, but shops use it freely, and not always honestly — “ergonomic” on a packet may only mean “we bent it a little.” Strictly it is an adjective: ergonomic design, an ergonomic keyboard. The subject of that design is ergonomics. Though actually, good fit depends on the person; what is ergonomic for one body may not be for another.