calyx
noun [ C ] biology specialized uk/ˈkeɪ.lɪks/ us/ˈkeɪ.lɪks/ calyces uk/ˈkeɪ.lɪ.siːz/ us/ˈkeɪ.lɪ.siːz/ calyxes
花萼（位于花的外侧，有若干萼片组成，开花时起到保护花瓣的作用）
the outer part of a flower formed by the sepals (= the separate outer parts), which covers and protects the petals, etc. as they develop