French Compound Noun Plurals: Essential Rules and Examples

French compound nouns can be tricky when it comes to forming their plurals. Unlike in English, where we simply add an "s" to most nouns, French has specific rules depending on the components of the compound noun.

Let's break down these rules and provide plenty of examples to help you grasp this important aspect of French grammar.

General Rules for French Compound Noun Plurals

Before diving into specific cases, here are two general rules to keep in mind:

1. Nouns, adjectives, and past participles typically follow normal pluralization rules.
2. Verbs, prepositions, adverbs, and pronouns usually remain unchanged (invariable).

Now, let's explore the most common types of compound nouns and their plural forms.

Noun + Noun Combinations

When Both Nouns Are Equally Important

In this case, both nouns become plural.

Examples:

• un oiseau-mouche → des oiseaux-mouches (hummingbird(s))
• un chou-fleur → des choux-fleurs (cauliflower(s))
• un wagon-lit → des wagons-lits (sleeping car(s))

When One Noun Modifies the Other

Here, only the first noun becomes plural.

Examples:

• un soutien-gorge → des soutiens-gorge (bra(s))
• un arc-en-ciel → des arcs-en-ciel (rainbow(s))
• un chef-d'œuvre → des chefs-d'œuvre (masterpiece(s))

Noun + Adjective Combinations

In most cases, both the noun and adjective become plural.

Examples:

• un coffre-fort → des coffres-forts (safe(s))
• un pied-plat → des pieds-plats (boor(s))
• un grand-père → des grands-pères (grandfather(s))
• une belle-fille → des belles-filles (daughter(s)-in-law, step-daughter(s))

Exceptions

Some adjectives remain invariable:

• Adjectives ending in -o: des Anglo-Saxons (Anglo-Saxons)
• The adjective "demi": des demi-bouteilles (half bottles)

Adjective + Adjective Combinations

Both adjectives typically become plural.

Examples:

• une douce-amère → des douces-amères (woody nightshade)
• un sourd-muet → des sourds-muets (deaf-mute(s))

Adverb + Noun Combinations

Only the noun becomes plural in these cases.

Examples:

• une arrière-cour → des arrière-cours (backyard(s))
• un haut-parleur → des haut-parleurs (loudspeaker(s))

Adverb/Adjective + Past Participle

The past participle becomes plural, while the adverb or adjective remains unchanged.

Examples:

• un nouveau-né → des nouveau-nés (newborn(s))
• un bien-aimé → des bien-aimés (beloved(s))

Preposition + Noun

The noun becomes plural, but the preposition stays the same.

Examples:

• une contre-offensive → des contre-offensives (counter-offensive(s))
• un en-tête → des en-têtes (heading(s))
• un après-midi → des après-midis (afternoon(s))

Verb + Noun

The pluralization depends on the nature of the noun:

Concrete and Countable Nouns

The noun becomes plural.

Examples:

• un brise-glace → des brise-glaces (icebreaker(s))
• un couvre-lit → des couvre-lits (bedspread(s))

Abstract or Collective Nouns

Traditionally, these compound nouns were invariable. However, the 1990 spelling reform allows the noun to be pluralized.

Examples:

• un porte-monnaie → des porte-monnaie or des porte-monnaies (change purse(s))
• un gratte-ciel → des gratte-ciel or des gratte-ciels (skyscraper(s))

Verb + Verb Combinations

These compound nouns remain invariable.

Examples:

• un laissez-passer → des laissez-passer (pass(es))
• un va-et-vient → des va-et-vient (comings and goings)

Conclusion

French compound noun plurals follow specific patterns based on their components. By understanding these rules and practicing with examples, you'll improve your French grammar skills significantly.