basse-cour, basses-cours, poultry-yard, poultry-yards.
porte-cochère, portes-cochères, carriage entrance, carriage entrances.
N. B.--Peculiar are:
grand'mère, grand'mères, grandmother, grandmothers.
grand'messe, grand'messes, high mass, high masses.
monsieur, messieurs, mister, sir, gentlemen.
madame, mesdames, madam, ladies.
mademoiselle, mesdemoiselles, miss, young ladies.
4. When a compound is formed of a noun joined to either a verb, a preposition, or an adverb, then the noun alone takes the sign of the plural--provided, however, it conveys the idea of plurality, as:
passe-port, passe-ports, passport, passports.