鼻子 (bí·zi) is the standard colloquial term for 'nose' in Mandarin Chinese. The first character, 鼻 (bí), means 'nose' on its own and appears in formal or compound words like 鼻腔 (bí qiāng, 'nasal cavity') or 鼻炎 (bí yán, 'rhinitis'). The second character, 子 (zi), is a common noun suffix that adds a neutral, familiar, or slightly diminutive tone—making the word sound natural in everyday speech, especially when referring to the human body part. Unlike the more literary or medical term 鼻 (bí) alone, 鼻子 is universally used in daily conversation, children’s language, and informal descriptions.

This word appears frequently in health-related contexts (e.g., catching a cold, allergies), sensory expressions (e.g., smelling something), and idioms (e.g., 摸着石头过河, though not directly involving nose). It's also used metaphorically in some fixed phrases, such as 鼻子都气歪了 ('so angry one’s nose twists'), emphasizing emotional reaction. As a concrete body-part noun, it follows standard noun grammar: it can be modified by measure words like 个 (gè), appear after possessive pronouns (e.g., 我的鼻子), and serve as subject or object in sentences.