/sem'ee seuhb merr"seuh beuhl, sem'uy-/ , n.
1. Also called semisubmersible rig . a self-propelled barge that is mounted on partially submerged legs supported by underwater pontoons, rides at anchor, and serves as a work base and living quarters in deep offshore drilling operations.
adj.
2. of, for, or pertaining to a semisubmersible.
[ 1960-65; SEMI- + SUBMERSIBLE ]