laugh vs sight gag

laugh and sight gag both are nouns.

Word	Noun	Adjective	Verb	Adverb
laugh	Yes	No	Yes	No
sight gag	Yes	No	No	No

As nouns, sight gag is a hyponym of laugh; that is, sight gag is a word with a more specific, narrower meaning than laugh:

laugh: a humorous anecdote or remark intended to provoke laughter
sight gag: a joke whose effect is achieved by visual means rather than by speech (as in a movie)

laugh (noun)	sight gag (noun)
the sound of laughing	a joke whose effect is achieved by visual means rather than by speech (as in a movie)
a humorous anecdote or remark intended to provoke laughter
a facial expression characteristic of a person laughing

laugh (verb)	sight gag (verb)
produce laughter