means A person employed to clean, maintain, and look after a building.

from Straight from Latin janitor, 'doorkeeper,' built on janua, 'door,' which itself traces back to Janus — the two-faced Roman god of doorways, beginnings, and thresholds, who looked both inward and outward at once. So the modern caretaker with the mop and the master key inherits the name of the god who guarded every passage; the job drifted over the centuries from watching doors to tending the whole building behind them.