medium3 noun (plural mediums) [countableC]
medium• Poetry is the best medium for this sort of thing, he says.• But whatever the subject, the mood was predominantly one of escape and the medium one of romance.• Either answer is partially correct, as the method of absorption varies with different concentrations of nutrients in the medium.• These models were the medium they used to communicate.• The transfer medium is magnetic tape.• Watercolour is taken to include gouache and bottle artists' colour as well as the traditional transparent medium.
From Longman Business Dictionary
mediumme·di·um1 /ˈmiːdiəm/ adjectiveadj of middle size, between small and large
Disposable nappies come in small, medium and large sizes.
Small and medium firms will benefit most from the new rules.