Seam (7)
'seam' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for layer that I've seen before include "Seam" , "Bed - hen" , "Blanket - single thickness" , "Early (anag.)" , "Stratum; chicken" .)
'seam' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for stratum that I've seen before include "Bed of sedimentary rock" , "(Geological) layer" , "stretch of rock" , "rock band" , "Layer (of rock)" .)
(Other definitions for hem that I've seen before include "It draws attention to" , "may attract attention" , "Express hesitation" , "Sewn edge to fabric" , "Double-backed cloth border" .)