accompaniment vs happening

accompaniment and happening both are nouns.

Word	Noun	Adjective	Verb	Adverb
accompaniment	Yes	No	No	No
happening	Yes	No	No	No

As nouns, happening is a hypernym of accompaniment; that is, happening is a word with a broader meaning than accompaniment:

accompaniment: an event or situation that happens at the same time as or in connection with another
happening: an event that happens

Other hypernyms of accompaniment include natural event, occurrence, occurrent.

accompaniment (noun)	happening (noun)
the act of accompanying someone or something in order to protect them	an event that happens
something added to complete or embellish or make perfect
a musical part (vocal or instrumental) that supports or provides background for other musical parts
an event or situation that happens at the same time as or in connection with another