pecker vs Picus viridis

pecker and Picus viridis both are nouns.

Word	Noun	Adjective	Verb	Adverb
pecker	Yes	No	No	No
Picus viridis	Yes	No	No	No

As nouns, Picus viridis is a hyponym of pecker; that is, Picus viridis is a word with a more specific, narrower meaning than pecker:

pecker: bird with strong claws and a stiff tail adapted for climbing and a hard chisel-like bill for boring into wood for insects
Picus viridis: woodpecker of Europe and western Asia

pecker (noun)	Picus viridis (noun)
bird with strong claws and a stiff tail adapted for climbing and a hard chisel-like bill for boring into wood for insects	woodpecker of Europe and western Asia
horny projecting mouth of a bird
obscene terms for penis