名詞 fifty:

1. the cardinal number that is the product of ten and five
   同義詞：50, L
2. a United States bill worth 50 dollars
   同義詞：fifty dollar bill

形容詞 fifty:

1. being ten more than forty
   同義詞：50, l

1. The World Cup final is being transmitted live to over fifty countries.
   世界杯決賽現(xiàn)在正向五十多個國家現(xiàn)場轉(zhuǎn)播。
2. The number of tigers has reduced abruptly in the last fifty years.
   在過去的五十年里，老虎的數(shù)目銳減。
3. There are more than fifty workers in this workshop.
   這個車間里有五十多個工人。
4. These people who were young fifty years back are now gray haired.
   50年前的年輕人，現(xiàn)在已經(jīng)白發(fā)蒼蒼了。
5. My mother is fifty years old.
   我母親已經(jīng)五十歲了。

fif.ty

n.（名詞）
The cardinal number equal to 5 × 0.
五十：等于5×0的基數(shù)
fifties
fifties
Often Fifties The decade from 50 to 59 in a century.
常作 Fifties 五十年代：在一個世紀(jì)中從50年到59年的十年
A decade or the numbers from 50 to 59:
五十到五十九：從五十到五十九之間的數(shù)字或五十到五十九歲之間：
例句：
They began playing golf in their fifties. With the sunshine, the temperature reached the fifties.
他們在五十幾歲時開始打高爾夫球的。在陽光照射下溫度達(dá)到了五十幾度

來源：
Middle English fifti
中古英語 fifti
from Old English foftig * see penk we
源自 古英語 foftig *參見 penk we

【引伸】
fif.ty
adj.（形容詞）
pron.（代詞）