Tapestry at first children weave (6)
I believe the answer is:
tissue
'weave' is the definition.
(I know that weave can be written as tissue)
'tapestry at first children' is the wordplay.
'at first' indicates taking the first letters.
'children' becomes 'issue' (issue can mean someone's offspring).
The initial letter of 'tapestry' is 't'.
't'+'issue'='TISSUE'
(Other definitions for tissue that I've seen before include "Bodily matter" , "Basic structural element of an animal or plant" , "light material" , "Suddenly leave in protest" , "Gauzy fabric" .)