a weapon used in the past consisting of a pole with three sharp metal points on the end

Neptune's trident 海神尼普顿的三叉戟

a type of ballistic missile (= explosive weapon) that is sent from under the sea

a Trident missile/submarine “三叉戟”弹道导弹／潜艇

The navy plans to move its Tridents. 海军计划调动其三叉戟潜艇。