Definition of "cactus" in English

noun

1. (botany) Any member of the family Cactaceae, a family of flowering New World succulent plants suited to a hot, semi-desert climate.

2. Any succulent plant with a thick fleshy stem bearing spines but no leaves, such as euphorbs.

adjective

1. (Australia, New Zealand, slang) Non-functional, broken, exhausted, dead.