紫

Nouns which may take the genitive case particle 'no'

purple; violet

Word usually written using kana alone

purple gromwell (Lithospermum erythrorhizon); red gromwell; red-root gromwell

soy sauce

purple; violet

purple smoke; tobacco smoke

purple lightning; flash; swordflash

Physics

ultraviolet rays; ultraviolet radiation; UV radiation

dark purple; bluish purple

aster (Aster tataricus); Tartarian aster; Michaelmas daisy

bigleaf hydrangea (Hydrangea macrophylla); French hydrangea

amethyst

Usu. as 紫がかった

to be purplish; to be tinged purple

rosewood; red sandalwood

Japanese beautyberry (Callicarpa japonica)

Bletilla striata (purple variety of orchid)

shiso (Perilla frutescens var. crispa); perilla; beefsteak plant

Buddhism

purple clouds on which Amitabha rides to welcome the spirits of the dead

Hall for State Ceremonies (in Heian Palace, Kyoto Imperial Palace, etc.)

Chinese milk vetch

purple vestment (traditionally awarded by the imperial household); high-ranking priest's purple robe

Abbreviation

Purple Forbidden Enclosure (group of constellations in the northern sky associated with the emperor)

flash of lightning; flash of a sword; brandishing a sword

Often called yams in America, but this is technically incorrect

purple fleshed sweet potato (any one of several different such)

Medal of Honor with Purple Ribbon (awarded for scholarly or artistic achievement)

Word usually written using kana alone

powdered oakblue (butterfly) (Narathura bazalus)

purple martin (bird) (Progne subis)

Medicine

purpura; purple spot