gherkin vs cucumber

gherkin and cucumber both are nouns.

Word	Noun	Adjective	Verb	Adverb
gherkin	Yes	No	No	No
cucumber	Yes	No	No	No

As nouns, cucumber is a hypernym of gherkin; that is, cucumber is a word with a broader meaning than gherkin:

gherkin: small prickly cucumber
cucumber: cylindrical green fruit with thin green rind and white flesh eaten as a vegetable; related to melons

Other hypernyms of gherkin include cuke.

gherkin (noun)	cucumber (noun)
small prickly cucumber	cylindrical green fruit with thin green rind and white flesh eaten as a vegetable; related to melons
any of various small cucumbers pickled whole	a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit