The term "surface threat" refers to the danger posed to ships and boats by attacks from above or below the waterline. It encompasses a range of potential hazards, including torpedoes, mines, missiles, and other weapons. Synonyms for this term might include "naval threat," "maritime danger," "oceanic peril," or "shipboard risk." Other related terms could be "underwater threat," "surface attack," or "seaborne hazard." In the context of military operations, these terms are often used to describe the challenges faced by naval forces in maintaining control of the seas and protecting their vessels from hostile forces.