Meaning of “size” - Learner’s Dictionary

size

noun uk us /saɪz/
HOW BIG [ C, U ]

A2 how big or small something is:

It's an area about the size of Oxford.
The size of some of those trees is incredible (= they are very large).
MEASURE [ C ]

A2 one of the different measurements in which things, for example clothes, food containers, etc are made:

a size 10 skirt
What size shoes do you take?
I usually buy the 1.5 litre size.
→ See also all shapes and sizes

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