(architecture) A vault resulting from the intersection of two barrel-vaults crossing in a right angle. Its thrusts are concentrated along the groins or arrises and eventually at the four corners

plural of double barrel vault

plural of double besom pocket

A pocket on the inside of a garment accessed through a slit with a reinforced upper and lower edges, with no flap.

(nautical) To perform the labour of three days in two.

(geometry) A configuration of 30 points and 12 lines. The lines can be partitioned into two subsets of six: each line is disjoint from (skew with) the lines in its own subset of six lines, and intersects all but one of the lines in the other subset of six lines. Each of the 12 lines of the configuration contains five intersection points, and each of these 30 intersection points belongs to exactly two lines, one from each subset.

A first cousin with whom one shares four grandparents (and hence is also a double cousin).

plural of double first cousin

(printing, US, dated) The size of type between double English and meridian, standardized as 36-point.

(printing, dated) A large size of type, standardized as (UK) 21- or (US) 22-point.