Forms: α. 3 (dative) cluse, 5–6 clowse, clowze, clouse, pl. clousis, clowses, 9 dial. cloose. β. pl. 5 clowys, 6– clowes, 9 cloughs; sing. 5 clowe, 7–9 clow, 8–9 clough; dial. clow, clew. [Clow is a false singular formed upon clowes, clowis, taken in 15–16th c. for a plural, but originally a singular, in ME. clowse, clowze, early ME. cluse, OE. chúse, a. late L. clūsa, var. of clausa, lit. a closed or shut place or way. Du Cange has, among other senses, ‘agger in quo concluduntur aquæ.’ Hence, also, OHG. chlûsa, MHG. klûse, klûs, mod.Ger. klause, in Bavaria and Tirôl, a dam on a mountain stream for floating timber; klaus, in Rhineland, a mill-dam, also dial. a sluice. So MDu. clûse, Du. kluis.
The OE. clús, clúse, is recorded in the senses ‘enclosure,’ ‘narrow pass,’ but not in that of ‘dam,’ ‘lock,’ or ‘sluice,’ though ‘dam’ appears already in Ancren Riwle in 13th c. In the 18th c. clow began to be erroneously spelt clough, by engineers, etc., either through erroneous identification with CLOUGH sb. ‘ravine,’ or by association with plow, plough. In some of the dialect glossaries it is spelt clew, meaning klū. An unexplained clowre, cloor, is found in Catholicon Anglicum, and northern dialects.
A compound of L. clūsa was exclūsa (in Gregory of Tours; in med.L. sclūsa, slūsa), giving OF. escluse, F. écluse. Hence Sc. CLUSS, clush; OF. gave MDu. sluyse, Du. sluys, whence Eng. sluice, LG. slūse, Ger. schleuse. Thus clows and sluice are ultimately closely related.]
1. † a. A dam for water, a mill-dam. ? Obs. b. A sluice or floodgate: ‘esp. (a) The outfall sluice of a river or drain communicating with a tidal river and provided with flood-gates.’ (b) ‘A shuttle in the gates or masonry of a lock, which is raised to admit or discharge water; a similar arrangement by which the admission of water to the wheels of water-mills is regulated.’ Peacock, Gloss. Manley and Corringham (N. W. Lincoln.).
α. cluse, clouse, clowze.
a. 1225. Ancr. R., 72. Auh moni punt hire worde uorte leten mo vt as me deð water et ter mulne cluse.
c. 1440. Promp. Parv., 84. Clowys, water schedynge [c. 1490 MS. K. clowse, watyrkepyng; MS. H. clowze; 1499 Pynson, clowse, water shettinge], sinoglocitorium.
1493. Acta Dom. Conc., 314 (Jam.). Tuiching the watter passagis & clousis of thar millis.
1503. Act Jas. IV., c. 72 (1597), 93. The slayers of Smoltes in milne-dames, clowses, and be nettes, thornes, and cruves.
1595. Duncan, Append. Etymol. (E. D. S.), Emissarium, a clowse.
1875. [See β] Cloose.
β. pl. clowes, clows, sing. clowe, clow.
1483. Cath. Angl., 68/2. A clowe of flodeȝate, singlocitorium, gurgustium.
1541. Act 33 Hen. VIII., c. 33. Diches and bankes, as of other clowes, sloweses, getties, gutters, gootes, and other fortresses.
1615. N. Riding Rec., II. 103. Ric. Cuthbert presented for pulling-up the mill-clowes.
1662. Dugdale, Embanking & Draining (1772), 165. A new gote, or clow, be set in Waynflet haven.
1693. Diary A. de la Pryme (1869), 272. It … runs into the sea … when the clow is opened.
1705. Sir W. Calverley, Note-bk. (Surtees), 106. Thomas Haighton … pulled down a stone or two of the clow, and one or two of the stones of the dam.
1805. R. W. Dickson, Pract. Agric. (1807), II. 435. Proper to have a flood-hatch or clow.
1861. Smiles, Engineers, I. 70. Vermuyden had erected a sluice, of the nature of a ‘clow,’ being a strong gate suspended by hinges, which opened to admit the egress of the inland waters at low tide, and closed against the entrance of the Thames when the tide rose.
1869. R. B. Peacock, Lonsdale Gloss., Clauw, a floodgate in a watercourse.
1875. Lanc. Gloss., Claw (Fylde), cleaw (S. & E. Lanc.), cloose (N. Lanc.), clow (E. & M. Lanc.), a floodgate in a watercourse.
1884. Holland, Chester Gloss., Clew, a door or lid hung at the end of a drain or watercourse to prevent the influx of tidal water.
γ. 8– clough.
1774. Bainton Inclos. Act, 12. Banks, cloughs, engines.
1839. Stonehouse, Axholme, 377. Here also the Croule warping cloughs, which are on a very large scale, receive their waters from the Trent.
1865. W. White, E. Eng., II. 6. Clough—pronounced with the same terminal sound as plough—is the local word for a sluice-gate.
1884. York Herald, 26 Aug., 1/2. The Cloughs at Naburn Lock will be drawn at six o’clock in the morning (weather permitting).
δ. 5 clowre(?), 9 dial. cloor.
1483. Cath. Angl., 68. A Clowe of flodeȝete [A Clowre or flodȝate A.].
1847–78. Halliwell, Cloor, a sluice. Northumb.
1878. Cumberland Gloss., Cloor-head, a sluice at the head of a mill-dam.
2. A sluice or sliding door for other purposes.
1820. W. Scoresby, Arctic Reg., II. 399. A ‘fenk-back’ or depository for the refuse of the blubber … sometimes provided with a clough on the side next the water, for ‘starting’ the fenks into a barge or lighter placed below.
1874. W. Crookes, Dyeing & Calico-Printing, 84. By stirring up the wool in a tank…, the water being let off through a ‘clow’ or shuttle, furnished with a grating, at the bottom of the vat.
3. Floating Clow (clough): a name sometimes given to a contrivance for clearing away mud from channels communicating with tidal rivers (e.g., the Humber, where the local name is ‘Devil’). It resembles a broad barge, with extensible wings which act as floodgates, and retain a head of water, by which it is forced down the channel, plowing or scraping up the mud as it goes along.
1874. in Knight, Mech. Dict.
