polypyoudaoicibaDictYouDict[polyp 词源字典]
polyp: [16] A polyp is etymologically a ‘manyfooted’ creature. The word originally signified ‘octopus’, but in the 18th century was broadened out into a general term for marine invertebrates with tentacles, such as hydras and sea anemones. It comes via French polype and Latin polypus from Greek polúpous ‘cuttlefish’, a compound formed from pólus ‘much, many’ and poús ‘foot’ (source of English pew and podium and related to English foot).

The metaphorical application of the word to a tumour growing from mucous membrane (an allusion to its tentacle-like outgrowths) originated in Greek. Greek pólus (a distant relative of English full and plural) is of course the starting point of many English poly- words, all with the underlying notion of ‘several’ – among them polyglot [17] (etymologically ‘many tongues’), polygon [16], polysyllable [16], and polytechnic [19].

And its plural, polloí ‘many’, is the origin of English hoi polloi [19], literally ‘the many’.
=> foot, full, hoi polloi, pedal, plural, plus, polygon[polyp etymology, polyp origin, 英语词源]
polyp (n.)youdaoicibaDictYouDict
c. 1400, "nasal tumor," from Middle French polype and directly from Latin polypus "cuttlefish," also "nasal tumor," from Greek (Doric, Aeolic) polypos "octopus, cuttlefish," from polys "many" (see poly-) + pous "foot," from PIE root *ped- (1) "a foot" (see foot (n.)). Etymological sense revived 1742 as a name for hydras and sea anemones (earlier polypus, early 16c.). The Latin word is the source of French poulpe "octopus."