a. Obs. Forms: 3 ðherk, 4–5 þerke, 5 therk, thirke, thyrke, 7 thurck, thurk. [app. a variant of ME. derk, DARK; but the change of initial d to ð, þ, is abnormal and unexplained: cf. however OS. thimm, beside OE. dim(m), OFris. dimme DIM.] = DARK a.
c. 1250. Ðherk [see TRERKNESS below].
13[?]. Sir Beues (A.), 2790. Til it was þe þerke niȝt.
c. 1430. Lydg., Min. Poems (Percy Soc.), 204. Your byl clothyd thirke and on clene.
c. 1440. Jacob’s Well, 219. Ffyve cytees schal be in þe lond of thirknes spekyng wyth a chaungyng tunge. Þis is for to saye, ffyve citees schal be in the therk body of man.
c. 1450. Cov. Myst., xvii. (1841), 170. To marre ȝow in a thyrke myste.
a. 1682. Sir T. Browne, Tracts, viii. (1684), 146. Words … of common use in Norfolk … as … Thurck.
1691. Ray, S. & E. C. Words, Tharky adj., ‘very tharky,’ very dark. Suff. … Thurk, Norf. Ibid., Pref. 5. Thurk is plainly from the Saxon deorc, dark.
Hence † Therk v. Obs. (3 þirk) = DARK v.; † Therkness Obs., darkness.
c. 1275. Lay., 11973. Þirkede vnder sonne Þustrede þe wolkne.
c. 1250. Gen. & Ex., 3102. Ðhikke ðherknesse cam on ðat lond.
c. 1440. [see above].
c. 1485. Digby Myst., III. 773. Owt of þe ded slep of therknesse de-fend vs aye!
