Eighteen
来自Big Physics
Old English e(a)htatēne (see eight, -teen).
wiktionary
From Middle English eiȝtetene, eiȝtene, ehtetene, from Old English eahtatīene, eahtatēne, from Proto-Germanic *ahtōutehun. Cognate with West Frisian achttjin, Dutch achttien, German achtzehn, Danish atten.
Equivalent to eight + -teen
etymonline
eighteen (adj., n.)
"1 more than seventeen, twice nine; the number which is one more than seventeen; a symbol representing this number;" late 14c., eightene, earlier ahtene (c. 1200), from Old English eahtatiene, eahtatyne; see eight + -teen. Cognate with Old Frisian schtatine, Old Saxon ahtotian, Dutch achttien, Old High German ahtozehan, German achtzehn, Old Norse attjan, Swedish adertån.
