We accept Henry as a member of the school (5)
I believe the answer is:
whale
'a member of the school' is the definition.
I can't tell whether this definition defines the answer.
'we accept henry' is the wordplay.
'accept' means one lot of letters goes inside another.
'henry' becomes 'hal' (short for Henry).
'we' enclosing 'hal' is 'WHALE'.
'as' is the link.
Can you help me to learn more?
(Other definitions for whale that I've seen before include "Great sea mammal" , "Largest animal" , "World's largest mammal" , "Mammoth marine mammal" , "Large marine mammal" .)