鼻塞 (bí sāi) literally means 'nose blockage' — 鼻 (bí) means 'nose', and 塞 (sāi) means 'to block' or 'to obstruct'. Together, they form a medical and everyday term for nasal congestion: the uncomfortable feeling of stuffiness or reduced airflow through the nasal passages, often caused by colds, allergies, or sinus inflammation. It’s a neutral, widely understood term used in both informal conversations and clinical settings.

This word is commonly used when describing cold or flu symptoms, discussing allergy relief, or seeking advice from doctors or pharmacists. Unlike more technical terms like 鼻炎 (bí yán, 'rhinitis'), 鼻塞 is accessible to all speakers and frequently appears in health advisories, over-the-counter medicine labels, and casual talk about feeling unwell. It does not imply severity — mild or temporary congestion qualifies as 鼻塞, and it’s rarely used metaphorically.