dun

Concise Oxford English Dictionary © 2008 Oxford University Press:
dun1

▶adjective of a dull greyish-brown colour. ▶noun

• 1 a dull greyish-brown colour.

• 2 a horse with a sandy coat, black mane, tail, and lower legs, and a dark dorsal stripe.

• 3 a subadult mayfly with drab, opaque wings, or a fishing fly imitating this.

– origin OE dun, dunn, of Gmc origin; prob. rel. to dusk.

Concise Oxford English Dictionary © 2008 Oxford University Press:
dun2

▶verb (duns, dunning, dunned) make persistent demands on (someone) for payment of a debt. ▶noun archaic a debt collector or an insistent creditor.

– origin C17 (as n.): perh. from obs. Dunkirk privateer (with connotations of piratical demands), or from the name of a Joe Dun, a well-known bailiff.

Concise Oxford English Dictionary © 2008 Oxford University Press:
dun3

▶noun Archaeology (often in place names) a stone-built fortified settlement in Scotland or Ireland, of a kind built from the late Iron Age to the early Middle Ages.

– origin C18: from Ir. dún, Sc. Gaelic dùn ‘hill or hill fort’.