鼻孔 (bí kǒng) literally means 'nose hole' — 鼻 (bí) means 'nose', and 孔 (kǒng) means 'hole' or 'opening'. Together, they refer specifically to the external openings of the nasal cavity: the nostrils. This is a standard anatomical term used in everyday speech, medical contexts, and descriptive writing. Unlike more technical terms like 鼻腔 (nasal cavity), 鼻孔 emphasizes the visible external apertures through which air enters and exits the nose.

The word is commonly used when describing physical appearance (e.g., flared or small nostrils), physiological reactions (like sniffing or breathing heavily), or hygiene (e.g., picking one’s nose). It appears in both formal and informal registers, though it’s neutral in tone — not clinical like 鼻前庭 (vestibule of nose), nor slangy like 鼻洞 (a rare, informal variant). Children learn this word early as part of body vocabulary, and it frequently appears in health education and biology lessons.