【Youth】 , 【adolescence】 ,  【puberty】 ,  【pubescence】  are sometimes used interchangeably to denote the period in life when one passes from childhood to maturity.

【Youth】 is the most general of these terms, being applied sometimes to the whole early part of life from childhood or infancy to maturity. More often, however,  【youth】  is applied to the period between the maturing of the sexual organs and the attaining of full maturity.  【Youth】  often connotes the freshness, vigor, inexperience, or impetuosity characteristic of the young.

【Adolescence】  designates the same period as  【youth】  in the restricted sense, but it carries a stronger connotation of immaturity.  【Adolescence】  suggests the awkwardness resulting from the rapid growth during this period and also the mental and emotional instability resulting from the physiological changes. In legal use  【adolescence】  designates the period extending from 【puberty】 to the attainment of full legal age or majority.

Basically  【puberty】  designates the age at which the signs of the maturing of the sexual organs appear (as the beard and changed voice in boys and the development of the breasts in girls); in law this age is commonly fixed at fourteen for boys and twelve for girls. In broader use  【puberty】  often designates the period covering the earlier years of 【adolescence】 during which the secondary sex characteristics are unfolding.

【Pubescence】  is sometimes used as equivalent to  【puberty】  , but often it applies distinctively to the condition of attaining the characteristics (as genital hair) of developing sexuality.