'Liǎng kǒu zi' literally means 'two mouths' — a colloquial, affectionate, and slightly rustic term for a married couple. The 'two mouths' metaphor reflects the idea of two people sharing one household, one life, and one set of daily needs (like eating from the same pot). It carries warmth and familiarity, often used in informal speech among family, neighbors, or older generations, especially when referring to long-married or down-to-earth couples.

The term emphasizes partnership and domestic unity rather than romantic or legal status; it’s rarely used for newlyweds or in formal contexts. While gender-neutral in reference, it usually implies a heterosexual couple in traditional usage — though modern speakers sometimes use it more flexibly. It’s not appropriate for official documents or formal writing, and never used to refer to oneself alone — always as a third-person or second-person plural reference ('they', 'you two').