What does interlock mean?
To interlock means to connect or lock things together so that they move, operate, or relate as a coordinated unit. The word is especially common in engineering, transport, manufacturing, and safety systems, where an interlock is a mechanism that prevents two parts from moving or operating independently. For example, a railway signal system may interlock the points and signals so that they cannot be activated in an unsafe combination. The noun can refer either to the device itself or, more generally, to a relationship in which several parts or activities are closely connected. In ordinary use, “interlocking” can suggest cooperation and careful coordination, especially among organizations or individuals whose decisions affect one another. The term is precise and technical but can also be used metaphorically in discussions of systems, institutions, and collaborative planning.
To lock or connect two or more things together so that they cannot move or operate independently; to fit together as a coordinated mechanism.
"The safety doors interlock to prevent the machine from starting while they are open."
Often used in technical and formal contexts, especially in engineering, transport, and safety systems.
A device or arrangement that prevents two parts from operating independently or simultaneously; also, a state of being connected in this way.
"The system includes an interlock that disables the press during maintenance."
The technical sense is common in machinery, transport, electrical systems, and industrial safety.
The plural is used for individual devices or mechanisms, as in “a system with three interlocks.”
"The new interlocks prevent the conveyor from moving while the gate is open."
From railway signals to laboratory equipment, interlocks act as mechanical guardians: they make it impossible for dangerous actions to happen at the same time.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does interlock come from?
Interlock was formed in the 19th century from the Latin-derived prefix inter-, meaning “between” or “among,” and the verb lock. The compound developed the sense of fastening together or coordinating parts so that they act as one. Its technical uses expanded alongside railway signalling, machinery, electrical systems, and later industrial safety equipment. The older words lock, unlock, and locker belong to the same Germanic root, while interact reflects the shared Latin prefix inter-.
Related word forms
How interlock is actually used
The word is formal and technical in most contexts, especially in engineering, transport, and safety systems. In general writing, it can describe people or organizations whose plans and activities are closely coordinated.
Easily confused with interlock
An interlock is a deliberate connection or safety mechanism that prevents independent action, whereas a deadlock is an unwanted situation in which participants wait for one another and progress stops.