... as a cub entangled in a counting frame (6)
I believe the answer is:
abacus
'a counting frame' is the definition.
(I've seen this before)
'as a cub entangled' is the wordplay.
'entangled' is an anagram indicator.
'as'+'a'+'cub'='asacub'
'asacub' anagrammed gives 'ABACUS'.
'in' is the link.
(Other definitions for abacus that I've seen before include "Very early calculator" , "calculator needed" , "Beaded counting frame" , "You could count on this once" , "Counting device" .)