1. a secret or underhand means of access (to a place or a position) - he got his job through the back door • Syn: back door • Hypernyms: access 2. an undocumented way to get access to a computer system or the data it contains • Syn: back door • Hypernyms: access, access code 3. an entrance at the rear of a building • Syn: back door, back entrance • Hypernyms: exterior door, outside door