mediation vs negotiation

mediation and negotiation both are nouns.

Word	Noun	Adjective	Verb	Adverb
mediation	Yes	No	No	No
negotiation	Yes	No	No	No

As nouns, negotiation is a hypernym of mediation; that is, negotiation is a word with a broader meaning than mediation:

mediation: a negotiation to resolve differences that is conducted by some impartial party
negotiation: a discussion intended to produce an agreement

Other hypernyms of mediation include dialogue, talks.

mediation (noun)	negotiation (noun)
the act of intervening for the purpose of bringing about a settlement	the activity or business of negotiating an agreement; coming to terms
a negotiation to resolve differences that is conducted by some impartial party	a discussion intended to produce an agreement