Strange dearth of yarn (6)
I believe the answer is:
thread
'yarn' is the definition.
(synonyms)
'strange dearth' is the wordplay.
'strange' indicates an anagram.
'dearth' is an anagram of 'THREAD'.
'of' is the link.
(Other definitions for thread that I've seen before include "Train of thought - screw feature" , "Cord - Internet chat room discussion" , "Connecting line" , "Sewing chord" , "Strand, cord" .)