(baseball) A pitch thrown with the arm motion of a fastball, but which travels at a much slower velocity because it is released without the fingers adding power to the delivery.

(physics) A quark having a fractional electric charge of +2/3 and a mass of about 1.5 to 4 MeV. / Symbol: u

Alternative form of wind-up

(literally, transitive) To wind completely (rope, string, mainsprings).

(Britain, informal) A party.

(transitive) To double the quantity, amount or duration of something / (poker, by extension, intransitive) To double one's amount of chips by winning an all-in pot.

(physics) the antiparticle of an up quark

Coming into view suddenly from a concealed position. / Opening out to form a three-dimensional structure when the page of a book is opened. / Operating or existing for a brief period only; temporary.

A pop-up advertisement; an advertisement that is triggered to appear on a computer screen when an Internet user accesses a particular web page.

Used other than figuratively or idiomatically: see run, up. / To run (towards someone or something); to hasten to a destination. / (with to) To approach (an event or point in time).