(chemistry) Any nucleophylic compound that can donate a pair of electrons and form a coordinate covalent bond.

(chemistry) Any compound, of general formula Xⁿ⁺, which can be transformed into a conjugate acid HX⁽ⁿ⁺¹⁾⁺ by the gain of a proton.

A parachute jump from a fixed point rather than from an aircraft; typically from a tall building, high bridge or rock formation.

(intransitive) To make such a jump.

(baseball) To touch a base, usually with a foot but sometimes with a hand.

(baseball) A base without a runner on it.

(baseball) The base after second base in a counter-clockwise path around a baseball infield. / (blackjack) The betting spot located immediately to the right of the dealer, which is last to act.

(singular only, baseball) The base after home plate in a counter-clockwise path around a baseball infield. / (singular only, by extension) Completion of the first phase of an activity.

(baseball) The base opposite home plate in a baseball infield. / (singular only, US, colloquial) Touching a partner under his or her clothes, without having sex.

(obsolete, 1800s) baseball