Compound Word Formation

A compound word (palavra composta) is built by combining two or more existing words — not by adding affixes to a single stem, but by gluing whole words together. Portuguese compounds are everywhere: guarda-chuva (umbrella), porta-voz (spokesperson), couve-flor (cauliflower), fim-de-semana (which AO90 actually splits into three separate words, see below). Each compound has its own little internal grammar — a hyphenation pattern, a gender, a pluralization rule — and these have been the source of more spelling reforms than almost any other corner of Portuguese morphology.

This page covers the morphology of compounding in PT-PT under the Acordo Ortográfico 1990: which structural patterns Portuguese uses, how the components combine, what hyphen the AO90 demands (or strips), and how to pluralize compounds when the head and the modifier do not always agree on number. The topic is small, but the details matter — getting the pluralization wrong on a common compound is one of the most visible spelling slips in PT-PT.

What counts as a compound?

A Portuguese compound is two or more words written as a unit, often with a hyphen, that together name a single concept. The unit behaves as a single noun (or adjective): it has one gender, one plural, and one syntactic position.

The Portuguese tradition distinguishes two structural mechanisms:

1. Juxtaposition (justaposição) — the components keep their independent spelling, usually joined by a hyphen. Guarda-chuva, couve-flor, porta-voz, pé-de-meia.
2. Agglutination (aglutinação) — the components fuse into a single word, with phonetic adjustments. Vinagre (vinho + acre), aguardente (água + ardente), fidalgo (filho + de + algo).

Agglutination is historical — you cannot create a new agglutinative compound today. Juxtaposition is still productive: new compounds appear in the press, in product names, and in everyday speech.

Juxtaposition with hyphen

The most common compounding mechanism in modern PT-PT. The components retain their spelling and are linked by a hyphen.

Verb + noun — the most productive pattern

A third-person singular verb form joined to a noun (its object). The compound names a tool, an agent, or a thing characterized by the action. This is the single most productive compounding pattern in modern PT-PT — new compounds in this shape appear regularly.

Productivity test: you can coin new compounds in this pattern. Lava-loiça (dishwasher) and aspirador robô (robot vacuum — borrowed structure) are recent. Espalha-brasas (someone who stirs up trouble — literally "spreads embers") shows the productivity in slang.

Noun + noun

Two nouns side by side, with the second qualifying or specifying the first. The first noun is usually the head (the one that determines gender and is pluralized).

Noun + adjective (or adjective + noun)

The noun is the head; the adjective qualifies it. The order can vary, and some compounds have a fixed adjective-first order for historical reasons.

Preposition-linked compounds (with de, less commonly a)

A frequent PT-PT compound type uses de (or rarely a) as a connector between the components. These almost always retain their hyphens under AO90.

Juxtaposition without hyphen — agglutination

A small but important class of compounds where the components have fully fused into a single word. They are written solid, often with phonetic adjustments, and a naive speaker would not necessarily recognize them as compounds.

Agglutination is closed. Modern PT-PT does not produce new agglutinative compounds. The ones that exist are inherited from older stages of the language, and the original components are sometimes invisible to current speakers (embora feels like a single word, not em + boa + hora).

Compound types — a summary table

Gender of compounds

Knowing the gender of a compound is critical, because the article and any modifying adjectives must agree with it. Three principles:

1. Verb + noun compounds are usually masculine

Even when the noun part is feminine. The compound takes its gender from the type of thing it names (a tool, an agent, an action), not from the gender of the noun inside it.

2. Noun + noun compounds take the gender of the head (usually the first noun)

3. Preposition-linked compounds usually take the gender of the first noun

Pluralization of compounds

The pluralization of compound words is a notorious headache, even for native speakers. Three patterns:

Pattern A — only the head pluralizes

When the head is identifiable and the modifier is invariant.

Pattern B — neither component pluralizes

When the verb part is invariant (always third-person singular) and the noun part is already plural in form, the whole compound is invariant.

Pattern C — both elements pluralize

When both components inflect together, especially in noun + adjective compounds where the adjective is gradable.

Decision summary for pluralization

AO90 hyphenation: what changed for compounds

The Acordo Ortográfico 1990 reformed hyphenation rules. For compound words, the most important changes:

Compounds that lost their hyphens

Compounds that kept their hyphens

Most lexicalized compounds — those that name a specific thing, especially the verb + noun pattern — keep their hyphens.

The general rule: if the compound names a single, conventionalized concept, the hyphen stays. If it is a free-form combination of separable elements, AO90 prefers writing them as separate words.

Prefix + noun compounds

For compounds formed with a prefix (which we cover more fully on the common prefixes page), the AO90 rule is:

• Use a hyphen when the stem begins with the same letter as the prefix ends with, or with h: anti-higiénico, super-resistente, contra-ataque.
• Otherwise no hyphen: antibiótico, autoestrada, antifascista, semicírculo.

Compound adjectives

Most of this page has focused on compound nouns, but compound adjectives also exist. Some patterns:

Adverb + participle / adjective

Compound colour adjectives

A characteristic PT-PT pattern: colour names made by combining cor + de + noun. These function as invariable adjectives — they do not change for gender or number.

Note that cor-de-rosa and cor-de-laranja do not pluralize: uma blusa cor-de-rosa, duas blusas cor-de-rosa. This is a quirk of compound adjectives based on a noun comparison ("the colour of rose," "the colour of orange") — the noun reference does not change.

Compounds and translation patterns

Many Portuguese compounds correspond to single English nouns or to English compounds with very different structure. A few correspondences worth noting:

The PT-PT pattern (verb-noun) maps to English compounds in different shapes. Don't expect a one-to-one structural correspondence.

Common mistakes

Key takeaways

• A Portuguese compound combines two or more existing words into a single unit, usually written with a hyphen: guarda-chuva, couve-flor, porta-voz, pé-de-meia.
• The verb + noun pattern is the most productive in modern PT-PT: third-person singular verb + a noun naming what the verb acts on. Abre-latas, saca-rolhas, guarda-chuva.
• Agglutination (full fusion: vinagre, aguardente, fidalgo, embora) is historical and no longer productive.
• Gender: verb + noun compounds default to masculine, even with a feminine internal noun. Noun + noun compounds take the gender of the head (usually the first noun). Preposition-linked compounds also follow the head.
• Pluralization: usually only the head noun pluralizes. Verb + noun compounds with a plural noun part (abre-latas, para-quedas) are invariant. Both elements pluralize in noun + adjective compounds (obras-primas, cofres-fortes).
• Cor-de-rosa, cor-de-laranja, cor-de-vinho are invariable adjectives — no gender or number agreement.
• AO90 changes: fim-de-semana → fim de semana (three words), auto-estrada → autoestrada (fused), most lexicalized compounds keep their hyphens.
• Compound adjectives include adverb + participle types (bem-disposto, mal-educado, recém-nascido) and the colour compounds.
• When in doubt about a compound's plural or gender, the Vocabulário Ortográfico Português (VOP) and Priberam are the standard PT-PT references.