The spinnaker sail owes its name to a specific vessel, the yacht 'Sphinx'. After this yacht raced with the novel sail in 1866, the term 'Sphinx's acre' or a similar phrase was humorously applied to the sail. Through folk etymology, the name was subsequently altered to 'spinnaker', assimilating it to the familiar verb 'spin', which evocatively suggests the sail's billowing, rotating motion when deployed. This process of reanalysis and phonetic reshaping is common in nautical terminology, where practical usage often trumps etymological purity. Thus, a proper name transformed into a standard technical term through a blend of historical accident and associative meaning.

The word is a simplex. It is a 19th-century coinage, likely derived from the name of the yacht 'Sphinx', which first used such a sail in an 1866 race. The alteration to 'spinnaker' is influenced by the verb 'spin' and follows a pattern similar to other sail names (e.g., 'jib', 'mainsail').