coomb1

[koom, kohm] /kum, koʊm/
noun
1.
Also, coombe.

coomb2

[koom] /kum/
noun
1.
coom.
British Dictionary definitions for coomb

coom

/kuːm/
noun
1.
(dialect, mainly Scot & Northern English) waste material, such as dust from coal, grease from axles, etc
Word Origin
C16 (meaning: soot): probably a variant of culm1

coomb

/kuːm/
noun
1.
(mainly Southern English) a short valley or deep hollow, esp in chalk areas
2.
(mainly Northern English) another name for cirque
Word Origin
Old English cumb (in place names), probably of Celtic origin; compare Old French combe small valley and Welsh cwm valley
Word Origin and History for coomb
n.

also combe, "deep hollow or valley, especially on flank of a hill," mainly surviving in place names, from Old English cumb, probably a British word, from Celtic base *kumbos (cf. Welsh cwm in same sense). Cambridge Dictionary of English Place-Names says, "This is usually taken to be a Celtic loan ... but there was also OE cumb 'vessel, cup, bowl,'" which was "probably used in a transferred topographical sense reinforced in western districts by cwm."