splashdown vs landing

splashdown and landing both are nouns.

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

As nouns, landing is a hypernym of splashdown; that is, landing is a word with a broader meaning than splashdown:

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

splashdown (noun)	landing (noun)
a landing of a spacecraft in the sea at the end of a space flight	the act of coming to land after a voyage
	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