A pH indicator and red dye used to test kidney function.

A red soil found in tropical areas, containing oxidized iron.

Corymbia calophylla (marri), native to Western Australia, with red gum effusions / Eucalyptus camaldulensis (Murray red gum, river red gum), a eucalyptus tree with red wood.

Any of a variety of red or purple pigments containing ferric oxide, found in natural earth or made by chemical methods like calcinating green copperas.

Having the colour of Indian red pigment.

†Aphanapteryx bonasia, an extinct species of birds from the family Rallidae, formerly endemic to Mauritius.

(astronomy) A large red coloured star with a lower surface temperature than many stars, being at the final stage of moderately massive main-sequence stars.

A clover, Trifolium pratense, with red flowers, found in Europe, Asia and North America.

A strip of red carpet that is laid for a VIP to walk on. / (figuratively) VIP treatment.

A bright red and black butterfly, Vanessa atalanta, of the family Nymphalidae.