Etymology: Originally (in α. forms) partly < (i) post-classical Latin coccus coconut (although this is apparently first attested slightly later than the English word: 1557 or earlier), and partly (in later use) < (ii) Dutch †coquos (1584 as plural noun, earliest in †coquos noten : see coconut n.), †cocos (1596 as plural noun; now kokos ; also 1643 as †cocus ), both ultimately < Portuguese coco (see below). In β. forms probably partly < (iii) Spanish coco (1526), apparently a parallel formation to Portuguese coco , and partly < (iv) Italian †coco (1514, originally denoting the palm; now cocco (1583)), and its etymon (v) Portuguese coco (1553 or earlier; 1498 as †coquos , plural noun, in Vasco da Gama's Roteiro; for the ulterior etymology of the Spanish and Portuguese nouns, see below). The γ. forms appear to show an innovation in English, probably reflecting the unfamiliar shape of the word in English at this date. Perhaps compare Dutch (now regional) kokernoot coconut (1659 as †kokerneut ). N.E.D. (1891) comments that the spelling coker ‘has long been in commercial use at the port of London to avoid the ambiguity of cocoa ’. The δ. forms probably at least partly result from confusion with cacao n. (compare forms at that entry, and compare cocoa n.); because of the partial formal overlap between the entries cacao n., coco n., and cocoa n., quotations have been assigned to them on semantic principles (although in some early instances it may be difficult to determine precisely which fruit or nut is intended). This confusion appears to have been reflected in (and subsequently perpetuated by) Johnson's Dictionary (1755), which has a single entry with the headword cocoa, etymologized from Spanish cacao (compare cocoa n., cacao n.), followed by a list of illustrative quotations which includes instances where the coco palm and its fruit are intended as well as passages which refer to Theobroma cacao. The ε. forms apparently arose from influence between the γ. and δ. forms. Further cognates or parallels. Compare (all directly or indirectly < Portuguese) Middle French coco (1555; 1525 (in a translation from Italian) as coche ; French coco , also †cocos (1610)), and also German Kokos (1669 as †Coquos , plural noun), Swedish kokos (1675 as †cocos ). Compare also post-classical Latin and scientific Latin cocos (1623 or earlier; 1753 as genus name: Linnaeus Species Plantarum II. 1188), post-classical Latin cocus (1641 or earlier). In most Romance languages, as well as in post-classical Latin, the parallel nouns are first attested denoting the fruit, rather than the tree that bears it. Ulterior etymology. Portuguese coco and Spanish coco ‘coconut’ appear to show parallel extended uses respectively of Portuguese coco and Spanish coco ‘mask or object used to frighten children, bugbear’ (although the Portuguese word may be first attested slightly later in that sense: late 15th or early 16th cent.; Spanish coco ‘round mask, bugbear’ occurs a1480), both < a base of imitative origin also seen in coccus n. and in a large number of words for (chiefly) spherical objects (chiefly in children's language) in various Romance languages, e.g. Spanish coca head (1438), French coque shell (see coque n.). The name was apparently given to the fruit on account of the face-like appearance of the base of the coconut shell, which has three holes; this resemblance of shape is already mentioned in the first half of the 14th cent. in Ibn Battuta's Travels. (The etymological link with a word for a monkey's cry suggested in quot. 1555 at sense 1aα. appears to reflect a misapprehension.) Borrowing of the name from a non-European language is unlikely, since no similar forms have been identified in this sense in any of the languages spoken in India, where the Portuguese first encountered the fruit. See further the detailed discussion in J. Corominas Diccionario crítico etimológico castellano e hispánico (ed. 2, 1981) at coco I. Earlier names of the fruit. The coconut was earlier known in post-classical Latin as nux indica (see nux indica n., and compare later Indian nut n.), although that term was ambiguous, and could refer to various nuts used for medicinal purposes. Cosmas Indicopleustes (first half of the 6th cent.) used Byzantine Greek καρύον Ὶνδικόν to denote (probably) the coconut. Specific senses. With the use in sense 3, compare later coconut n. 3 and see the note at that sense. In quot. 1604 at sense 3 after Spanish coco (1590 in the passage translated, in uncertain sense, probably ‘Brazil nut’). With later quots. for this sense compare coco de mer n. and discussion at that entry, and also sea coconut n. 1. In quot. 1796 at sense 3 after French coco double (1773 in de Saint-Pierre's account of his voyage to Mauritius, or earlier)).

Etymology: < cocoa n., apparently as rhyming slang for so adv. and conj. in ‘say so’ or ‘think so’.