I like this poet's new elementary forms (8)
I believe the answer is:
isotopes
'elementary forms' is the definition.
Although both the answer and definition are plural nouns, I can't see how they can define each other.
'i like this poet's new' is the wordplay.
'like this' becomes 'so'.
'new' is an anagram indicator.
'poets' is an anagram of 'topes'.
'i'+'so'+'topes'='ISOTOPES'
Can you help me to learn more?
(Other definitions for isotopes that I've seen before include "Poet is so confused about forms of chemical elements" , "Stoops, i.e. to become odd types of atoms" , "what may be used for diagnostic purposes" , "Variant forms of element" , "atomic elements" .)