sequoia UK /səˈkwɔɪ.ə/US /sɪˈkwɔɪ.ə/ noun2 •Sequoiadendron giganteum, a coniferous evergreen tree formerly in the genus Sequoia, now placed in Sequoiadendron. •Sequoia sempervirens, a coniferous evergreen tree, the only living species of the genus Sequoia. formssequoias