Doc with meter reviewed layer of embryo (8)
I believe the answer is:
ectoderm
'layer of embryo' is the definition.
'ectoderm' can be an answer for 'layer' (I have seen 'Embryonic layer' mean 'ectoderm' so perhaps 'layer' could also mean 'ectoderm'). I'm not certain of the 'of embryo' bit.
'doc with meter reviewed' is the wordplay.
'with' says to put letters next to each other.
'reviewed' indicates an anagram (To look at again and re view).
'doc' put after 'meter' is 'meterdoc'.
'meterdoc' anagrammed gives 'ECTODERM'.
Can you help me to learn more?
(Other definitions for ectoderm that I've seen before include "outer part" , "Embryo's outermost layer of cells" , "outer layer" , "Embryonic layer" , "Early nervous stage" .)