肿 (zhǒng) is the specific term for body tissue swelling due to injury or infection — visible, often painful swelling like a sprained ankle. Unlike 胀 (zhàng), which describes an internal feeling of bloating or distension, 肿 is external and usually a medical symptom. 鼓 (gǔ) means 'to bulge' from internal pressure, while 膨胀 (péngzhàng) is a broader term for physical or metaphorical expansion.