landing vs splashdown

landing and splashdown both are nouns.

Word	Noun	Adjective	Verb	Adverb
landing	Yes	No	No	No
splashdown	Yes	No	No	No

As nouns, splashdown is a hyponym of landing; that is, splashdown is a word with a more specific, narrower meaning than landing:

landing: the act of coming down to the earth (or other surface)
splashdown: a landing of a spacecraft in the sea at the end of a space flight

Other hyponyms of landing include touchdown, aircraft landing, airplane landing.

landing (noun)	splashdown (noun)
the act of coming to land after a voyage	a landing of a spacecraft in the sea at the end of a space flight
the act of coming down to the earth (or other surface)
structure providing a place where boats can land people or goods
an intermediate platform in a staircase