Meaning of “inch” - Learner’s Dictionary

inch

noun [ C ] us uk /ɪntʃ/
She had a 26 inch waist.One metre is equal to 39.37 inches.I've lost two inches around my bust.You need a cake tin that's around ten inches in diameter.Measurements were given in feet and inches.

B1 written abbreviation in. a unit for measuring length, equal to 2.54 centimetres

not budge/give an inch informal
to be every inch sth

to be a particular kind of person in every way:

He is every inch a gentleman.

(Definition of “inch noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)