n.

1. 青春时代，青少年时期[U]
   I spent my youth in the country.

   我在乡间度过了青少年时代。

2. （男）青年，小伙子[C]
   There are groups of youths playing basketball over there.

   那里，一群群小伙子正在打篮球。

3. 青年们[the S][（+of）][G]
4. 年轻；朝气；青春[U]
   My youth has gone.

   我的青春已不复存在。

5. 初期；早期[U]
   Cryonics is still in its youth.

   人体冷冻学还处于初始阶段。

n.

1. the period between childhood and adult age.
   ▸the qualities of vigour, freshness, immaturity, etc. associated with being young.
2. [treated as sing. or pl.] young people.
   ▸a young man.