(US, motor racing) Collectively, both the Indianapolis 500, a day race, and the Coca-Cola 600, an evening race, both of which are run on Memorial Day weekend Sunday. Used concerning racers who (wish[/ed/ing] to) participat[e/ed/ing] in both events, typically using a private jet to travel between Indianapolis, Indiana, after the 500 and Charlotte, North Carolina, to get to the 600.

Twice over; twofold; doubly. / Two together; two at a time. (especially in see double)

Twice the number, amount, size, etc. / A person who resembles and stands in for another person, often for safety purposes / A drink with two portions of alcohol.

(transitive) To multiply by two. / (intransitive) To increase by 100%, to become twice as large in size. / To be the double of; to exceed by twofold; to contain or be worth twice as much as.

present participle of double

The process or an instance of making something double; a multiplication by two. [from 14th c.] / The act of turning around, or doubling back. [from 16th c.] / A pleat or fold. [from 17th c.]

plural of double

(sports, plural only) a game between pairs of players / (campanology, plural only) bell changes rung on five bells

Third-person singular simple present indicative form of double

(idiomatic) Rapidly or immediately.