Board one first writes on (7)
I believe the answer is:
pension
'board' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'one first writes on' is the wordplay.
'one' becomes 'i' (Roman numeral).
'first' says to put letters next to each other.
'writes' becomes 'pens' ('pen' can be a synonym of 'write').
'i' put after 'pens' is 'pensi'.
'pensi'+'on'='PENSION'
Can you help me to learn more?
(Other definitions for pension that I've seen before include "Retired person's income" , "Regular payment for older people" , "Nice little hotel" , "what oldies may have earned" , "Bed and breakfast or small hotel in France" .)