waste material, such as dust from coal, grease from axles, etc
Word origin
C16 (meaning: soot): probably a variant of culm1
coom in American English
(kuːm)
nounchiefly Scot & Northern English
1.
soot; coal dust; smut
2.
dust, esp. sawdust or dust from a gristmill
3.
grease from bearings, axles, etc
Also: coomb
Word origin
[1580–90; var. of culm1]This word is first recorded in the period 1580–90. Other words that entered Englishat around the same time include: bomb, classical, cockpit, motor, reference