天花

Originally the Chinese translation of several Sanskrit and Pali words, including Sanskrit खपुष्प (khapuṣpa, “flower in the sky”), as well as several plant names, such as Sanskrit दिव्यपुष्प (divyapuṣpa, “oleander ”) / Pali devapuppha, and Sanskrit शालपुष्प (śālapuṣpa, “confederate rose ”).

The development from “heaven-flower” (or other interpretations of the combination) to “smallpox” is unknown. It may be due to the shape resemblance of smallpox pustules to the divine flowers in Buddhism. Compare Tibetan ལྷ་འབྲུམ (lha 'brum, “smallpox ”), མེ་ཏོག (me tog, “flower; (dialectal) smallpox”), and Mongolian ᠰᠠᠯᠬᠢᠨ
ᠴᠡᠴᠡᠭ (salkin čečeg) / салхин цэцэг (salxin ceceg, “smallpox; chickenpox ”).

天花

1. (Buddhism) flower of the sky; divine flower, stated in the Lotus Sutra as of four kinds, two white and two red
2. (literary, poetic) snowflake; snow
3. (pathology) smallpox; variola
4. Short for 天花板 (tiānhuābǎn, “ceiling”).

• (flower of the sky): 天華／天华, 空華／空华
• (snowflake): 雪花 (xuěhuā)
• (smallpox): 天然痘 (tiānrándòu); (TCM) 痘瘡／痘疮 (dòuchuāng)

天(てん)花(か) • (tenka) 

1. snow
2. a flower that blossoms in the Buddhist heaven by their tale.
3. lotus-petal-shaped confetti scattering before the mortuary tablet.