spat vs class Bivalvia

spat and class Bivalvia both are nouns.

Word	Noun	Adjective	Verb	Adverb
spat	Yes	No	Yes	No
class Bivalvia	Yes	No	No	No

spat (noun)	class Bivalvia (noun)
a young oyster or other bivalve	oysters, clams, scallops, mussels
a cloth covering (a legging) that covers the instep and ankles
a quarrel about petty points

spat (verb)	class Bivalvia (verb)
clap one's hands together
spawn
engage in a brief and petty quarrel
clap one's hands or shout after performances to indicate approval
strike with a sound like that of falling rain
become permanently attached
come down like raindrops