interlock

verb
     
in‧ter‧lock [intransitive and transitive]
if two or more things interlock, or if they are interlocked, they fit firmly together:
a puzzle with 500 interlocking pieces

Dictionary results for "interlock"
Dictionary pictures of the day
Do you know what each of these is called?
What is the word for picture 1? What is the word for picture 2? What is the word for picture 3? What is the word for picture 4?
Click on any of the pictures above to find out what it is called.