interlock

Concise Oxford English Dictionary © 2008 Oxford University Press:
interlock/ɪntəˈlɒk/

▶verb (of two or more things) engage with each other by overlapping or fitting together.

■ lock or join (things) together.

▶noun

• 1 a device or mechanism for connecting or coordinating the function of components.

• 2 (also interlock fabric) a fabric with closely interlocking stitches allowing it to stretch.

– derivatives
interlocker noun.