6. (Engin.) The efficiency of an engine, especially a steam pumping engine, as measured by work done by a certain quantity of fuel; usually, the number of pounds of water lifted one foot by one bushel of coal (94 lbs. old standard), or by 1 cwt. (112 lbs., England, or 100 lbs., United States).
7. (Com.) Tax, toll, impost, or customs; excise; any sum of money required by government to be paid on the importation, exportation, or consumption of goods.
An impost on land or other real estate, and on the stock of farmers, is not called a duty, but a direct tax. [U.S.]
Ad valorem duty, a duty which is graded according to the cost, or market value, of the article taxed. See Ad valorem. -- Specific duty, a duty of a specific sum assessed on an article without reference to its value or market. -- On duty, actually engaged in the performance of one's assigned task.
||Du*um"vir (?), n.; pl. E. Duumvirs (#), L. Duumviri (#). [L., fr. duo two + vir man.] (Rom. Antiq.) One of two Roman officers or magistrates united in the same public functions.
Du*um"vi*ral (?), a. [L. duumviralis.] Of or belonging to the duumviri or the duumvirate.
Du*um"vi*rate (?), n. [L. duumviratus, fr. duumvir.] The union of two men in the same office; or the office, dignity, or government of two men thus associated, as in ancient Rome.
||Dux (?), n. [L., leader.] (Mus.) The scholastic name for the theme or subject of a fugue, the answer being called the comes, or companion.
||Duy"ker*bok (?), n. [D. duiker diver + bok a buck, lit., diver buck. So named from its habit of diving suddenly into the bush.] (Zoöl.) A small South African antelope (Cephalous mergens); -- called also impoon, and deloo.
Du*young" (?), n. (Zoöl.) See Dugong.
D" valve` (?). (Mech.) A kind of slide valve. See Slide valve, under Slide.
||Dver"gr (?), n.; pl. Dvergar (#). [See Dwarf.] (Scand. Myth.) A dwarf supposed to dwell in rocks and hills and to be skillful in working metals.
Dwale (?), n. [OE. dwale, dwole, deception, deadly nightshade, AS. dwala, dwola, error, doubt; akin to E. dull. See Dull, a.] 1. (Bot.) The deadly nightshade (Atropa Belladonna), having stupefying qualities.
2. (Her.) The tincture sable or black when blazoned according to the fantastic system in which plants are substituted for the tinctures.