Plural Form of Compound Nouns

General Rules

Combination	Pluralization	Singular Form	Plural Form
noun + noun	add "-s" to the second noun or "-ies" if it ends in the letter y.	action moive bar soap parking ticket business activity case study government agency	action movies bar soaps parking tickets business activities case studies government agencies
noun + ful	add "-s" at the end of the word	mouthful spoonful bucketful bowlful handful	mouthfuls spoonfuls bucketfuls handfuls
adjective + noun	add "-s" at the end of the word. if the noun is multisyllabic and ends in "y", chaange it to "-ies".	active ingredient joint account married couple rainy day valid reason clean energy dead body ethnic minority foreign policy	active ingredients joint accounts married couples rainy days valid reasons clean energies dead bodies ethnic minorities foreign policies
verb + preposition	add "-s" at the end of the preposition instead of the verb	check-in checkout login log out grown-up drawback takeoff	check-ins checkouts logins log outs grown-ups drawbacks takeoffs
noun + prepostion	add "-s" at the end of the noun	passer-by hanger-on love-in	passers-by hangers-on loves-in
noun + prepositional phrase	add "-s" at the end of the noun	mother-in-law father-in-law sister-in-law brother-in-law daughter-in-law son-in-law	mothers-in-law fathers-in-law sisters-in-law brothers-in-law daughters-in-law sons-in-law