Toy block name (4)
I believe the answer is:
lego
'toy block name' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lego that I've seen before include "Kids' bricks" , "Children's building bricks" , "Toy consisting of interlocking plastic bricks" , "Small bricks" , "Toy with interlocking blocks" .)