Some verse as a sequence (8)
I believe the answer is:
quatrain
'some verse' is the definition.
(thesaurus)
'as a sequence' is the wordplay.
'as' becomes 'qua' ('qua' is a Latin term meaning 'in the capacity of').
'a sequence' becomes 'train' (I've seen this before).
'qua'+'train'='QUATRAIN'
(Other definitions for quatrain that I've seen before include "Poem of four lines found in a quart" , "Poet may write it" , "Four-lined verse" , "Type of verse with four lines" , "poetic lines" .)