[f. CAP + STONE.]
1. A stone that caps or crowns: a. the top-stone. Also fig.
1685. Gracian’s Courtier’s Orac., 150. Here is the fair occasion … to put the cap-stone upon his other perfections.
1791. Smeaton, Edystone L., § 293. They had put on the cap-stone of the stair-head.
1863. Cowden Clarke, Shaks. Char., xvi. 447. The capstone to his revelry is when he accepts Falstaff’s pledge to a bumper.
b. The overlying horizontal stone of a cromlech or dolmen.
1851. D. Wilson, Preh. Ann. (1863), II. 9. Much greater mechanical skill … was required to … upheave the capstone of the cromlech on to the upright trilith.
1879. Lubbock, Addr. Pol. & Educ., ix. 157. A dolmen … of which only the capstone now remains.
c. Coping-stone, coping.
1665. Lond. Gaz., No. 6/1. The Sea here threw up several Capstones and Keys.
1828–41. Tytler, Hist. Scot. (1864), I. 137/1. The assailants would drag the ship so near the walls as to be able to fix their movable bridges on the capstone.
d. The uppermost bed of stone in a quarry.
1791. Smeaton, Edystone L., § 108. Were it not for these cavities, the cap-stone would not readily be worked.
2. Geol. A fossil Echinite of the genus Conulus, so called from its cap-like shape.
1677. Plot, Oxfordsh., 92. By the Country people called commonly Cap-stones, from their likeness to a Cap laced down the sides.
