An innings is one of the divisions of a cricket match during which one team takes its turn to bat. Innings, in cricket, is both singular and plural which contrasts with baseball and softball in which the singular is "inning".
The earliest known record of the term concerns a match on Wednesday, 5 August 1730 at Blackheath, Kent
between Kent and London. The London-based newspaper St. James Evening Post
reported on Saturday, 8 August: "'Twas thought that the Kentish champions would have lost their honours by being beat at one innings if time had permitted". This is the first time that the word "innings" is found in contemporary records. Incidentally, it is also the first time that the word "champions" is found in a team sense, which is significant because it confirms that the idea of a champion county was already well established among cricket's followers. Furthermore, the match was apparently drawn and is the earliest known instance of this result.
[Buckley, p. 4.] [Maun, p. 130.]
Usage in cricket
An innings is one of the divisions of a match during which one team takes its turn to bat. Innings is the subject of Law 12 in the Laws of cricket.
In a first-class match, there are up to four innings with each team due to bat twice (in practice, this is not always the case). In a limited overs match, there are only two innings with each team batting once. The term is also used with the meaning of "score" for both the team and each individual batsman. For example, it may be said that "he played an innings of 101", meaning that the player scored 101 in his innings. Similarly, it may be said that the team had a first innings (score) of 501.
The term can generally be taken as a reference to the time during which someone possesses something and, colloquially, the phrase "a good innings" means a long life.
[Chambers, p. 768.] [Oxford, p.733.]