Definition of jenny wren:
(n) :
(UK) The wren, Troglodytes troglodytes, especially as considered (in nursery-rhymes, etc.) as the wife or sweetheart of robin redbreast.
(n) :
(Australia) a female blue wren, or a male blue wren in non-breeding plumage.
(n) :
(US) Synonym of herb Robert.