How to Say Rule, Ruler and Period in Portuguese

How do you say rule in Portuguese? It depends on which "rule" you mean, because here in Brazil we don't use one word for everything: a rule as in a norm is regra, the ruler you measure with is régua, and a woman's period is menstruação.

The tricky part is that regra and régua look and sound almost the same, a bit like "rule" and "ruler" in English. That's why so many learners mix up regra vs régua and end up saying things that sound pretty funny to us Brazilians. And if you also speak Spanish, it gets even more confusing, since Spanish uses a single word, "regla", for all three meanings.

Whether you're looking for the word for ruler in Portuguese or a natural way to talk about menstruation in Portuguese, here I'll explain what regra means, what a régua is, how to say period in Portuguese in both formal and casual ways, and other related words like regulamento, vida regrada and trena, always with real examples of how we talk in Brazil.

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Régua vs Regra

Régua: a measuring tool (like a school ruler).
Regra: a rule, norm, instruction or law.

Examples in Portuguese:

• Peguei a régua pra medir a folha.
• As regras do jogo são bem simples.
• Você leu todas as regras do contrato?

How to Say "Period" (Menstruation) in Portuguese

In Portuguese, "regra" is never used to talk about menstruation. The correct word is:

Menstruação (the more formal, medical term).

Here's a definition of menstruation written in Portuguese:

Menstruação é o processo natural onde o revestimento interno do útero (endométrio) é descartado, saindo pelo sangue e tecidos pela vagina, como parte do ciclo menstrual que prepara o corpo para uma possível gravidez; se não há fecundação, esse tecido é expelido, regulado por hormônios como estrogênio e progesterona, ocorrendo mensalmente na vida reprodutiva, da puberdade à menopausa, com ciclos variando de 21 a 35 dias e fluxo durando de 3 a 7 dias.

People also use casual expressions like:

• Tô naqueles dias
• A menstruação desceu
• Tô de bode
• Tô de boi
• Tô de chico

Examples in Portuguese:

• Hoje não tô bem… tô naqueles dias.
• Minha menstruação desceu ontem, tô com cólica.

Article in Portuguese: Como parar de menstruar? Veja remédios, chás e dicas seguras

Regulamento: Rules and Regulations

When you mean the official set of rules of a contest, a company or a building, Portuguese uses "regulamento", the equivalent of "regulations" or "bylaws" in English. Spanish speakers often say "reglamento" by mistake, but that word doesn't exist in Portuguese.

Examples in Portuguese:

• Você conhece o regulamento do concurso?
• Isso está fora do regulamento da empresa.
• Esse tipo de negócio deveria ser regulamentado.

Vida regrada

This expression is very common in Portuguese and has no literal English translation. It means living a very disciplined life, with lots of rules or restrictions, something like "living by the book" or "keeping a strict routine".

Examples in Portuguese:

• Ele leva uma vida regrada, dorme cedo e come certinho.
• Quem treina na academia costuma ter dieta regrada.

Article in Portuguese: Dieta saudável: como preparar um cardápio para emagrecer.

Metro vs Trena

In Portuguese, "metro" is the unit of measurement (a meter), but it's not what you call the tool you measure with. A tape measure in Portuguese is called trena.

The word metro can refer to:

• A unit of length (a meter)
• Public transportation, the subway (metrô), with a slightly different pronunciation: the stress moves to the last syllable, "meh-TROH", while the meter is "MEH-troo"

Examples in Portuguese:

• Me empresta a trena pra medir essa parede?
• Preciso de um metro de tecido.
• Vou pegar o metrô até o centro.

Differences like these may look small, but they make a huge difference in understanding real, everyday Portuguese. They'll help you communicate with more confidence in real situations when you're in Brazil.

Masculine and feminine words in Portuguese