stingray, specifically whiptail stingray, more specifically red stingray

failing grade

Alternative spelling of 赤ずきん

a red deer

a red panda

a large Japanese field mouse

Synonym of ドール (dōru, “dhole”)

Red Square (a square in Moscow, Russia)

red line / (historical) Short for 赤線地帯(あかせんちたい) (akasenchitai): Akasen (districts in Japan where prostitution and the sex industry flourished)

"red sheet", specifically a red translucent plastic sheet used in studying to render red-colored text illegible