a fluid- or air-filled cavity or sac, in particular 泡;囊,尤指 ■(Anatomy & Zoology)a small fluid-filled bladder, sac, cyst, or vacuole within the body (剖,动)囊,泡 ■(Botany)an air-filled swelling in a plant, especially a seaweed (植)(植物,尤指海藻的)小泡,泡囊 ■(Geology)a small cavity in volcanic rock, produced by gas bubbles (地质)气泡 ■(Medicine)a small blister full of clear fluid (医)小水疱