Huge kids' publication - son is absorbed (6)
I believe the answer is:
cosmic
'huge' is the definition.
(thesaurus)
'kids' publication son is absorbed' is the wordplay.
'kids' publication' becomes 'comic'.
'son' becomes 's'.
'is absorbed' means one lot of letters goes inside another.
'comic' going around 's' is 'COSMIC'.
(Other definitions for cosmic that I've seen before include "Of the universe, infinite" , "Huge" , "Johann Sebastian --" , "Of the universe, immense" , "To do with the whole universe" .)