Stroke seabird: that's an order (7)
I believe the answer is:
pattern
'that's an order' is the definition.
(thesaurus)
'stroke seabird' is the wordplay.
'stroke' becomes 'pat' (pat can mean to stroke or touch).
'seabird' becomes 'tern' (tern is a kind of seabird).
'pat'+'tern'='PATTERN'
(Other definitions for pattern that I've seen before include "Stencil" , "Model or design from which to make clothes, say" , "A guide for making something" , "Repeated design; model" , "Sewing plan" .)