Meaning of “fraction” - Learner’s Dictionary

fraction

noun [ C ] us uk /ˈfrækʃən/
PART

a number less than 1, such as 1/2 or 3/4

AMOUNT

a very small number or amount:

a fraction of a second
fractionally adverb

by a very small amount:

Harry is fractionally taller than Ben.

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