"very hot day," 1874, agent noun from scorch (v.). It also means or has meant "stinging rebuke or attack in words" (1842), "pretty girl" (1881), "line drive in baseball" (1900).

also wheelhouse, 1835, "structure enclosing a large wheel," especially one over the steering wheel of a steamboat, thus "pilot house;" from wheel (n.) + house (n.). Baseball slang sense of "a hitter's power zone" attested by 1990.

1630s, "outlying land of a farm" (especially in Scotland), from out- + field (n.); sporting sense is attested from 1851 in cricket, 1868 in baseball, "part of the field most remote from the batsman/batter." Related: Outfielder.

late 15c., "egress," from out (adj). From 1620s, "a being out" (of something), from out (adv.). From 1764 in politics as "the party which is out of office." From 1860 in the baseball sense "act of getting an opposing player out of active play." From 1919 as "means of escape; alibi."

familiar or colloquial shortening of Philadelphia, attested by 1890, but from 1858 as the popular name of a ferry boat of that name that crossed the Delaware River from the city to Camden, and a city baseball team has been called the Phillies since 1883.

early 14c., "one who works in a field," agent noun from field (n.). Sporting sense is from 1832 (in cricket; by 1868 in baseball). Earlier in cricket was simply field (1825) and fieldsman (1767).

"boy who retrieves balls that go out of play during a game or match," 1896, in tennis, from ball (n.1) + boy. By 1955 in baseball. Ball-girl in tennis is by 1953.

1570s, "consisting of flakes," from flake + -y (2). Meaning "eccentric, crazy" first recorded 1959, said to be American English baseball slang, but probably from earlier druggie slang flake "cocaine" (1920s). Flake (n.) "eccentric person" is a 1968 back-formation from it. Related: Flakiness.

The term 'flake' needs explanation. It's an insider's word, used throughout baseball, usually as an adjective; someone is considered 'flaky.' It does not mean anything so crude as 'crazy,' but it's well beyond 'screwball' and far off to the side of 'eccentric.' [New York Times, April 26, 1964]

1911, American English, originally baseball slang; perhaps ultimately from jyng "a charm, a spell" (17c.), originally "wryneck" (also jynx), a bird used in witchcraft and divination, from Latin iynx "wryneck," from Greek iynx. Jynx was used in English as "a charm or spell" from 1690s.

Most mysterious of all in the psychics of baseball is the "jinx," that peculiar "hoodoo" which affects, at times, a man, at other times a whole team. Let a man begin to think that there is a "jinx" about, and he is done for for the time being. ["Technical World Magazine," 1911]

 The verb is 1912 in American English, from the noun. Related: Jinxed; jinxing. 

also rain-check, rain check, "ticket given to a spectator at an outdoor event for admission at a later date, or refund, should the event be interrupted by rain," 1884; see rain (n.) + check (n.1). Originally of tickets to rained-out baseball games.