means The act of setting something up so it's ready to use — software, a fixture, an appliance, or a person taking on an official role — or the thing thus set up.

from From Latin 'installare,' built from 'in-' (in) plus 'stallum' (a stall or seat), itself borrowed from a Germanic root for a standing-place — the same family that gives us 'stall' and 'stand.' The original sense was ceremonial: to formally 'seat' a cleric or official in his stall, his appointed place in the choir or chapter. The mechanical and digital senses — bolting in a boiler, loading software — came later, the word quietly migrating from putting people in their seats to putting things in their places.