islandyoudaoicibaDictYouDict[island 词源字典]
island: [OE] Despite their similarity, island has no etymological connection with isle (their resemblance is due to a 16th-century change in the spelling of island under the influence of its semantic neighbour isle). Island comes ultimately from a prehistoric Germanic *aujō, which denoted ‘land associated with water’, and was distantly related to Latin aqua ‘water’.

This passed into Old English as īeg ‘island’, which was subsequently compounded with land to form īegland ‘island’. By the late Middle English period this had developed to iland, the form which was turned into island. (A diminutive form of Old English īeg, incidentally, has given us eyot ‘small island in a river’ [OE].) Isle [13] itself comes via Old French ile from Latin insula (the s is a 15th-century reintroduction from Latin).

Other contributions made by insula to English include insular [17], insulate [16], insulin, isolate (via Italian) [18], and peninsula [16].
=> eyot[island etymology, island origin, 英语词源]
island (n.)youdaoicibaDictYouDict
1590s, earlier yland (c. 1300), from Old English igland "island," from ieg "island" (from Proto-Germanic *aujo "thing on the water," from PIE *akwa- "water;" see aqua-) + land (n.). Spelling modified 15c. by association with similar but unrelated isle. An Old English cognate was ealand "river-land, watered place, meadow by a river." In place names, Old English ieg is often used of "slightly raised dry ground offering settlement sites in areas surrounded by marsh or subject to flooding" [Cambridge Dictionary of English Place-Names]. Related: Islander.