Meaning of M in English

M

M BrE AmE , m /em/ ( plural M’s , m’s ) noun

1 . [uncountable and countable] the 13th letter of the English alphabet

2 . [countable] the number 1,000 in the system of ↑ roman numeral s

3 . M6, M25 etc the name of a ↑ motorway in Britain

Longman Dictionary of Contemporary English.      Longman - Словарь современного английского языка.