of middle size, level, or amount: ! Use average, not 'medium', when you want to say that someone's level of skill or activity is neither high nor low: Her standard is average (NOT Her standard is medium).
What size shirt does he wear - small, medium or large?
(of) medium height/length/build
She's of medium height.
hair of medium length
Fry the onions over a medium heat until they are golden.
medium to large companies
2 also medium rare
meat that is medium or medium rare is partly cooked but still slightly pink inside [↪ rare, well-done]
medium dry wine is slightly sweeter than dry wine
a colour which is neither light nor dark:
His jacket's a medium brown colour.