Pas de Calais vs Strait of Dover

Pas de Calais and Strait of Dover both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pas de Calais	Yes	No	No	No
Strait of Dover	Yes	No	No	No

As nouns, Pas de Calais and Strait of Dover are synonyms defined as:

Pas de Calais and Strait of Dover: the strait between the English Channel and the North Sea; shortest distance between England and the European continent

Other synonyms of Pas de Calais include Strait of Calais.

Pas de Calais (noun)	Strait of Dover (noun)
the strait between the English Channel and the North Sea; shortest distance between England and the European continent	the strait between the English Channel and the North Sea; shortest distance between England and the European continent