twofold; dual

Mrs Kimble was the Squire's sister, as well as the doctor's wife – a double dignity — George Eliot

consisting of two, usu combined, similar members or parts

of twice the usual size, quantity, etc

twice as great or as many

double the number of expected applicants

said of a drink: of twofold or extra size, strength, or value

designed or intended for two people

a double room

folded in two

said of a plant or flower: having more than the normal number of petals or sepals: compare single¹

said of a musical instrument: sounding an octave lower in pitch

a double bassoon

something twice the usual amount, number, size, etc, esp a double measure of spirits

somebody who takes the place of an actor in scenes calling for special skills or qualities

a sharp turn or twist

in bridge, a call that increases the value of tricks won or lost on an opponent's bid

the outermost narrow ring on a dartboard or a throw that lands there, counting double the stated score

to twice the extent or amount

two together

seeing double

to make or become twice as much or as many

to make a call in bridge that increases the value of tricks won or lost on (an opponent's bid)

to cause (a billiard ball) to rebound

to cause (troops) to move in double time

to sail around (a headland)

(+ back) to turn back on one's course

to reinforce (a musical note or part) with another at the same pitch or at an octave above or below

to become twice as much or as many

The cost has doubled

(+ up/over) to become bent or folded, usu in the middle

to double a bid (e.g. in bridge)

said of a billiard ball: to rebound