Answer: em

AnswerCrossword Clue
emend matched
emhaving the area of an em quad or the length of an em dash
emthe letter m
ema. the square of any size of type used as the unit of measurement for matter printed in that type size b. (originally) the portion of a line of type occupied by the letter M in type of the same size
emelectromagnetic
emunit of measurement equal to about one-sixth of an inch (4 mm)
emelectromotive
emgaseous product of radioactive disintegration, including radon, thoron, and actinon. Symbol: Em
emthe letter M, m
emEngineer of Mines
emelectronic mail
emenlisted man; enlisted men
emthe letter M
emelectron microscope; electron microscopy