MACHS is a playable word

mach Scrabble® Dictionary

noun
pl. machs
a number indicating the ratio of the speed of a body to the speed of sound
28 Playable Words can be made from "MACHS"
   2-Letter Words (7 found)
   3-Letter Words (9 found)
   4-Letter Words (9 found)
   5-Letter Words (3 found)