Lamb's nom-de-plume (4)
I believe the answer is:
elia
'lamb's nom-de-plume' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for elia that I've seen before include "Pseudonym of Charles Lamb, 1775-1834" , "Essays of - (Charles Lamb)" , "1A [SHEEPISH] part of 26 [LAMB-DA]" , "Pen-name of essayist Charles Lamb" , "Charles Lamb's pen name" .)