The English word “jack” can be traced back to the Latin Jacobus, “little Jacob”. In Old French it evolved into Jacques, with connotations of an inferior male, a peasant, or a servant. In Middle English, jacques became jack. “Jack” slowly came to be used with different shades of meaning that variously suggested: male, inferior man, inferiority, relative smallness, something that supported something larger. So in English lawn bowls, the little target bowl was the “jack” or the “jack-bowl”.
Allegedly William Shakespeare was a member of the Falcon Bowling Club in Pairswick. Perhaps the first written use in English of the word jack to refer to the little wooden target ball is in Shakespeare’s play Cymbeline (circa 1610), when a character named Cloten laments, “Was there ever man had such luck! When I kissed the jack, upon an up-cast to be hit away.”
In 1697 R. Pierce wrote “He had not strength to throw the Jack-Bowl half over the green”.
These references seem to come from John P. Monro, Bowls Encyclopaedia. For more information on the history of bowling games, see James Masters’ history of bowls games. But ignore his incorrect etymology of “jack-rabbit”. A jack rabbit is not a small rabbit. It is a “jackass rabbit”, a rabbit with big ears, like a jackass. A “jack” ass is a male ass; a female ass is a “jenny”.