*mak- Look up *mak- at Dictionary.com
*māk-, Proto-Indo-European root meaning "long, thin." It forms all or part of: emaciate; macro; macro-; macrobiotic; macron; meager; paramecium. It is the hypothetical source of Greek makros "long, large," mekos "length;" Latin macer "lean, thin;" Old Norse magr, Old English mæger "lean, thin."