porquê

Porquê is a masculine noun in Portuguese that designates the reason, cause, or justification for something. It refers to the grounds or rationale behind a fact, action, or situation, and is commonly used in formal or written language. The singular form is porquê, and the plural is porquês.

The expression can appear in phrases such as o porquê de algo or o porquê das coisas, where it functions as a nominalized concept rather than a question word. It is typically introduced by definite articles or demonstratives and can take a range of modifiers, just like other common nouns. In everyday speech, speakers may substitute mais simply with motivos or razões, but porquê remains a standard term in more literary or analytical contexts.

Distinctions from other forms of por- question words are important. Por que, two words, is used in direct or indirect questions meaning why or for which reason (Por que você saiu?); por quê, with an accent, is used at the end of a question or as a standalone question (Você saiu, por quê?). The one-word noun porquê is distinct from these question forms and should be treated as a noun rather than a interrogative.

Etymologically, porquê derives from the phrase linking por with quê, evolving over time into a fixed noun meaning the reason. Its use is widespread in both Brazilian and European Portuguese, though stylistic preferences may favor more concise alternatives in informal writing.