This person's vehicle - maybe repair? (6)
I believe the answer is:
iambus
'repair?' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'this person's vehicle' is the wordplay.
'this person's' becomes 'I am' ('this person' being the crossword setter).
'vehicle' becomes 'bus' (public transport vehicle).
'iam'+'bus'='IAMBUS'
'maybe' is the link.
Can you help me to learn more?
(Other definitions for iambus that I've seen before include "Metrical unit of two syllables" , "Type of metrical unit in a poem" , "poetic form" , "Metrical foot" .)