Meaning of MEDIUM in English
■ noun ( plural media or ~s )
1》 an agency or means of doing something.
↘the material or form used by an artist, composer, or writer.
2》 a substance through which sensory impressions are conveyed or physical forces are transmitted.
3》 a particular form of storage material for computer files, such as magnetic tape or discs.
4》 a liquid (e.g. oil) with which pigments are mixed to make paint.
5》 ( plural ~s ) a person claiming to be able to communicate between the dead and the living.
6》 the middle quality or state between two extremes.
7》 the substance in which an organism lives or is cultured.
■ adjective between two extremes; average.
C16: from L., lit. 'middle'.
Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004