(plural octopuses or octopodes or octopi) (see usage notes)
- Any of several marine molluscs/mollusks, of the family Octopodidae, having no internal or external protective shell or bone (unlike the nautilus, squid or cuttlefish) and eight arms each covered with suckers.
- (uncountable) The flesh of these marine molluscs eaten as food.
- An organization that has many powerful branches controlled from the centre.
The plural octopi is hypercorrect, coming from the mistaken notion that the -us in octopÅ«s is a Latin second declension ending. The word is actually treated as a third declension noun in Latin. The plural octopodes follows the Ancient Greek plural, á½€ÎºÏ„ÏŽÏ€Î¿Î´ÎµÏ‚ (oktÅpodes). The plural octopii is based on an incorrect attempt to pluralise the word based on an incorrect assumption of its origin, and is rare and widely considered to be nonstandard.
Sources differ on which plurals are acceptable: Fowler's Modern English Usage asserts that “the only acceptable plural in English is octopuses", while Merriam-Webster and other dictionaries accept octopi as a plural form. The Oxford English Dictionary lists octopuses, octopi, and octopodes (the order reflecting decreasing frequency of use), stating that the last form is rare.
The term octopod (either plural octopods and octopodes can be found) is taken from the taxonomic order Octopoda but has no classical equivalent, and is not necessarily synonymous (it can encompass any member of that order). The collective form octopus is usually reserved for animals consumed for food.
From Ancient Greek á½€ÎºÏ„ÏŽÏ€Î¿Ï…Ï‚ (oktÅpous), from á½€ÎºÏ„ÏŽ (oktÅ, “eight") + Ï€Î¿ÏÏ‚ (pous, “foot").
From Latin octopÅ«s, from Ancient Greek á½€ÎºÏ„ÏŽÏ€Î¿Î´ÎµÏ‚ (oktÅpodes, “eight feet").