[mag.ni.tude] n [ME, fr. L magnitudo, fr. magnus] (15c) 1 a: great size or extent b (1): spatial quality: size (2): quantity, number
2: the importance, quality, or caliber of something
3: a number representing the intrinsic or apparent brightness of a celestial body on a logarithmic scale in which an increase of one unit corresponds to a reduction in the brightness of light by a factor of 2.512
4: a numerical quantitative measure expressed usu. as a multiple of a standard unit