baptism vs sacrament

baptism and sacrament both are nouns.

Word	Noun	Adjective	Verb	Adverb
baptism	Yes	No	No	No
sacrament	Yes	No	No	No

As nouns, sacrament is a hypernym of baptism; that is, sacrament is a word with a broader meaning than baptism:

baptism: a Christian sacrament signifying spiritual cleansing and rebirth
sacrament: a formal religious ceremony conferring a specific grace on those who receive it; the two Protestant ceremonies are baptism and the Lord's Supper; in the Roman Catholic Church and the Eastern Orthodox Church there are seven traditional rites accepted as instituted by Jesus: baptism and confirmation and Holy Eucharist and penance and holy orders and matrimony and extreme unction

baptism (noun)	sacrament (noun)
a Christian sacrament signifying spiritual cleansing and rebirth	a formal religious ceremony conferring a specific grace on those who receive it; the two Protestant ceremonies are baptism and the Lord's Supper; in the Roman Catholic Church and the Eastern Orthodox Church there are seven traditional rites accepted as instituted by Jesus: baptism and confirmation and Holy Eucharist and penance and holy orders and matrimony and extreme unction