meter vs scansion

meter and scansion both are nouns.

Word	Noun	Adjective	Verb	Adverb
meter	Yes	No	Yes	No
scansion	Yes	No	No	No

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

Other hyponyms of meter include catalexis, common measure, common meter, foot, metrical foot, metrical unit.

meter (noun)	scansion (noun)
any of various measuring instruments for measuring a quantity	analysis of verse into metrical patterns
rhythm as given by division into parts of equal duration
(prosody) the accent in a metrical foot of verse
the basic unit of length adopted under the Systeme International d'Unites (approximately 1.094 yards)

meter (verb)	scansion (verb)
measure with a meter
stamp with a meter indicating the postage