a noun is a word that represents a person, place, thing, or concept. As a noun, 'laughter' refers to the vocal expression of amusement or mirth – a deep, idyllic, or unrestrained sound made as a response to something humorous or emotionally compelling.
when used as a noun, 'laughter' is always singular and can act as either the direct object or subject of a sentence.
The laughter coming from the living room was contagious.
His laughter lit up the room.
That joke wasn't funny, but her laughter made it seem so.
when used as a noun, 'laughter' is usually uncountable and should not be used with the indefinite article 'a' or 'an'.