earyoudaoicibaDictYouDict[ear 词源字典]
ear: Ear for hearing and ear of corn seem in some way to belong together, but in fact they are two quite distinct words etymologically. Ear for hearing [OE] is an ancient term that goes right back to the Indo-European roots of the language. Its ancestor is the base *aus-, whose underlying signification was perhaps ‘perception’ (a variant, *au-, produced Greek aisthánomai ‘perceive’).

This lies behind the term for ‘ear’ in the majority of European languages: French oreille, for example, Italian orecchio, Spanish oreja, Romanian ureche, Irish ó, Russian and Polish ucho, and modern Greek autí. Its Germanic descendant, *auzon, produced German ohr, Dutch oor, Gothic ausō, Swedish öra, and English ear.

The etymological sense of ear of corn [OE] is ‘spike’ of corn. The word comes from a prehistoric Germanic *akhuz, which goes back ultimately to the Indo-European base *ak- ‘be pointed or sharp’ (ultimate source of English acid, acne, acute, eager, edge, and oxygen).
=> acid, acne, acute, eager, edge, oxygen[ear etymology, ear origin, 英语词源]
ear (n.1)youdaoicibaDictYouDict
"organ of hearing," Old English eare "ear," from Proto-Germanic *auzon (cognates: Old Norse eyra, Danish øre, Old Frisian are, Old Saxon ore, Middle Dutch ore, Dutch oor, Old High German ora, German Ohr, Gothic auso), from PIE *ous- "ear" (cognates: Greek aus, Latin auris, Lithuanian ausis, Old Church Slavonic ucho, Old Irish au "ear," Avestan usi "the two ears").
þe harde harte of man, þat lat in godis word atte ton ere & vt atte toþir. [sermon, c. 1250]
In music, "capability to learn and reproduce by hearing," 1520s, hence play by ear (1670s). The belief that itching or burning ears means someone is talking about you is mentioned in Pliny's "Natural History" (77 C.E.). Until at least the 1880s, even some medical men still believed piercing the ear lobes improved one's eyesight. Meaning "handle of a pitcher" is mid-15c. (but compare Old English earde "having a handle"). To be wet behind the ears "naive" is from 1902, American English. Phrase walls have ears attested from 1610s. French orielle, Spanish oreja are from Latin auricula (Medieval Latin oricula), diminutive of auris.
ear (n.2)youdaoicibaDictYouDict
"grain part of corn," from Old English ear (West Saxon), æher (Northumbrian) "spike, ear of grain," from Proto-Germanic *akhuz (cognates: Dutch aar, Old High German ehir, German Ähre, Old Norse ax, Gothic ahs "ear of corn"), from PIE root *ak- "sharp, pointed" (source of Latin acus "chaff, husk of corn," Greek akoste "barley;" see acrid).