nine-inning

The compound "nine-inning" is a modern American English formation specific to the sport of baseball. The first element, "nine," derives from the ancient Germanic numeral, establishing the quantity. The second element, "inning," has a more complex journey from an Old English verb meaning "to get inside," evolving to signify a turn or period of play in games. In the context of baseball, established in the 19th century, an "inning" became one of two halves (top and bottom) of a turn at bat for each team. The compound adjective "nine-inning" logically fuses these concepts to describe the standard, complete duration of a regulation game, literally meaning "of or pertaining to nine divisions of play."

Structure: nine (number) + inning (division of a game) - nine: From Old English nigon, of Germanic origin; related to Dutch negen and German neun. Functions as a numerical determiner. - inning: From Old English inning 'a putting in, getting in', from innian 'to get within, put within'. In cricket and baseball, it came to denote a division of play. Functions as a noun.