[em-rey-dee-ey-shuh n] /ˈɛmˌreɪ diˌeɪ ʃən/
See under .
one of a series of lines (M-series) in the x-ray spectrum of an atom corresponding to radiation (M-radiation) caused by the transition of an electron to the M-shell.
Mental Retardation Association of America
1. medium-range ballistic missile. abbreviation 1. medium-range ballistic missile
abbreviation (in Britain) 1. Medical Research Council Medical Research Council