Hyphenation Rules

The hyphen (hífen) is the single most underestimated punctuation mark in modern European Portuguese. It looks small, but its rules are intricate, they were comprehensively rewritten by the Acordo Ortográfico 1990 (AO90), and getting them wrong is one of the most visible markers of pre-2009 spelling. This page walks through every situation where PT-PT uses (or no longer uses) a hyphen: with prefixes, inside compound nouns, in fixed expressions, in written-out numerals, in the names of weekdays, and at the end of a printed line. By the end, you should be able to predict the spelling of an unfamiliar prefixed word and recognise pre-AO90 forms when you see them in older texts.

Two warnings up front. First: the rules are mechanical but the inventory of cases is large — you will still meet edge cases that the rules don't decide cleanly, and PT-PT publishers occasionally tolerate two spellings for the same word. Second: this page deals with the typographic hyphen (-), not the em dash (—) used to open turns of dialogue. Those are two different marks doing two different jobs, and the page closes with a section on the dialogue dash so you don't confuse them.

With prefixes

Prefix-plus-stem spelling is governed by the AO90 hyphenation rules, summarised in Common Prefixes. Below is the trigger-by-trigger view, organised by what causes the hyphen to appear.

Trigger 1: stem begins with h

Most prefixes take a hyphen before a stem-initial h. The reasoning is etymological — the h is silent, and writing antihigiénico solid would obscure the morpheme boundary.

The two important exceptions — prefixes that never hyphenate, even before h — are des- and in-: desumano (inhuman), inábil (unskilled), desumidificar (to dehumidify). For these the h is dropped from the stem entirely.

Trigger 2: same vowel at the join

When the prefix ends in a vowel and the stem begins with the same vowel, you write a hyphen. This is the rule that keeps a doubled vowel from merging into one syllable.

Trigger 3: different vowels at the join — no hyphen

When the prefix ends in one vowel and the stem begins with a different vowel, the two are written solid (no hyphen). This is the change that surprises learners coming from pre-AO90 textbooks.

Trigger 4: stem begins with r or s — double the consonant, no hyphen

When the prefix ends in a vowel and the stem begins with r or s, AO90 says: drop the hyphen, double the consonant. The doubling preserves the original /ʁ/ or /s/ sound that would otherwise be softened by the surrounding vowels.

The principle is simple: a single r or s between vowels would be pronounced as a tap or as /z/ respectively. Doubling them preserves the strong /ʁ/ and /s/ sounds that the morpheme boundary would otherwise blur.

Trigger 5: stem begins with a different consonant — no hyphen

The default case. Prefix and stem fuse solid.

Trigger 6: special prefixes — always hyphenated

A handful of prefixes always take a hyphen, regardless of what the stem begins with. These are the ones that behave more like autonomous words attached to a base than like fused prefixes.

Compound nouns

Compound nouns (nomes compostos) form a parallel system. Whether they take a hyphen depends on the type of compound, and the rules are partly historical and partly typological.

Verb + noun → hyphen

Compounds built from a verb stem plus a noun are almost always hyphenated. The noun is typically the object of the verb action — the guarda-chuva is what the guarda (action of guarding) is for.

Noun + noun → hyphen (often)

Two nouns joined into a single concept usually take a hyphen, especially when the second noun specifies a kind of the first.

Adjective + noun → hyphen for new senses

When an adjective+noun combination forms a new lexical sense that the components alone don't carry, hyphenate. When the adjective is just modifying the noun in its normal way, no hyphen.

Noun + adjective: usually no hyphen

The reverse order — noun followed by adjective — is the unmarked Portuguese pattern (casa nova, carro azul) and almost never takes a hyphen, since it's just normal modification.

A small set of fixed combinations does take a hyphen because they form a single botanical, zoological, or geographic name: erva-doce (fennel), pimenta-rosa (pink pepper), erva-cidreira (lemon balm), pau-brasil (brazilwood).

Three-element compounds joined by de

Compounds where two nouns are linked by the preposition de often take two hyphens, treating the whole as one lexical unit.

Old fused compounds — no hyphen

Some compounds that historically had a hyphen (or two parts) have fused into a single solid word. These are listed in dictionaries and you simply have to know them.

Compound expressions: AO90 dropped many hyphens

The most visible AO90 change for everyday text concerns adverbial and prepositional expressions that used to be hyphenated and now are not. These caused a generation of confusion when they shifted in 2009.

In numerals written out

When you spell out numbers in PT-PT, the conjunction e (and) joins elements without hyphens. There are no compound-number hyphens of the vingt-et-un (French) or twenty-one (English-with-hyphen) sort.

So vinte-e-um (with hyphens) is wrong. The correct spelling is vinte e um. The same applies for all compound cardinals: quarenta e oito, sessenta e dois, novecentos e noventa e nove. See Cardinal Numbers 1-100 for the full inventory.

In days of the week

The five weekdays Monday through Friday are hyphenated compound nouns formed from an ordinal feminine adjective plus feira (literally "fair-day," from the medieval ecclesiastical calendar). They are always hyphenated and always lowercase.

In informal speech and writing, the -feira part is often dropped: Vemo-nos na segunda (See you on Monday). When abbreviated this way, no hyphen is used because the compound has been collapsed to its first element.

End-of-line word division (silabação)

When a word doesn't fit on a line and a printer or word processor breaks it across lines, the break must fall on a syllable boundary and is marked with a hyphen at the end of the upper line. The rules:

Break between syllables

Keep digraphs together

The digraphs ch, lh, nh, rr, ss, qu, gu represent single sounds and must stay on one line.

Note the last example: rr and ss are special — they represent single sounds but are written as two letters that fall on either side of the syllable boundary. So carro breaks as car-ro, missa as mis-sa. The other digraphs (ch, lh, nh, qu, gu) never split.

Break between consonants in a cluster

Don't leave a single vowel on a line

A single vowel cannot stand alone at the start or end of a line. Don't break eu into e-u.

In dialogue: the em dash, not the hyphen

European Portuguese fiction has a strong tradition of opening direct speech with the em dash (—), called travessão — not the hyphen (-). The em dash is wider and visually distinct. This is a punctuation choice that the hyphen rules do not govern, but it is worth flagging here because learners frequently confuse the two marks.

The em dash is also used parenthetically in the body of a sentence — much as English uses the em dash — to set off an aside. The hyphen would be wrong in this role: hyphens connect parts of a single word; em dashes separate parts of a sentence.

Common mistakes

Key takeaways

• AO90 governs all modern PT-PT hyphenation. Hyphen if the stem begins with h or with the same vowel that the prefix ends in; no hyphen otherwise.
• When the prefix ends in a vowel and the stem begins with r or s, the consonant doubles and there is no hyphen: antirreligioso, antissocial, autorretrato, cosseno.
• A handful of prefixes always take a hyphen: ex-, vice-, pós-, pré-, pró-, recém-, sem-, além-, aquém-.
• Compound nouns: verb+noun (guarda-chuva), most noun+noun (couve-flor), and many adjective+noun in new senses (amor-próprio) take hyphens. Plain noun+adjective modification (casa nova) does not.
• Three-element compounds joined by de take two hyphens: pé-de-meia, mão-de-obra, cão-de-guarda.
• Compound expressions like fim de semana, dia a dia, cara a cara lost their hyphens under AO90.
• Compound numerals are spelled with no hyphens, joined by e: vinte e um, cento e cinquenta.
• Weekday names are always hyphenated and always lowercase: segunda-feira, terça-feira, quarta-feira, quinta-feira, sexta-feira (Saturday and Sunday have no hyphen).
• The dialogue em dash (—) is a different mark from the hyphen (-). Don't substitute one for the other.