Nowadays learn layout of a gland (7)
I believe the answer is:
adrenal
'gland' is the definition.
(adrenal is a kind of gland)
'nowadays learn layout' is the wordplay.
'nowadays' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'layout' indicates an anagram (an alternative layout of the letters).
'learn' is an anagram of 'renal'.
'ad'+'renal'='ADRENAL'
'of a' acts as a link.
(Other definitions for adrenal that I've seen before include "close to the kidneys!" , "Relating to glands near the kidneys" , "(Gland) on the kidney" , "Glandular" , "Relating to certain glands" .)