A sort of tender name! (10)
I believe the answer is:
endearment
'a sort' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'of tender name' is the wordplay.
'of' indicates anagramming the letters (the answer comes from or 'of' the letters).
'tender'+'name'='tendername'
'tendername' with letters rearranged gives 'ENDEARMENT'.
Can you help me to learn more?
(Other definitions for endearment that I've seen before include "Term of affection" , "Fondness" , "Affectionate word" , "Expression of love" , "Affectionate term" .)