坛
tán · HSK 7
earthen jar
🏺 土 earth + 云 cloud = a jar thrown from clay; tán rhymes with 'on'
The 土 'earth/clay' radical on the left tells you the material: this is a vessel made of fired clay. Often a wide-mouthed crock for storing wine, pickles, or grain.
坛 — earth radical 土 + 云 (cloud/yun phonetic)
坛 is the simplified form of 壇, originally a phono-semantic compound with 土 (earth) giving the meaning of a raised earthen platform or altar, and 亶 supplying the sound. The simplified version swaps in 云 as a simpler phonetic. It later extended to mean a sealed jar or a community circle, as in 文坛 (literary world).