A pit or snare dug into the ground and disguised to catch animals or enemies

potential well in physics

Thucydides trap; the theory that war is likely when an established dominant power fears the rise of a rival power

a pit for catching animals or people; snare; pitfall

to hit someone when they are in trouble; to seize an opportunity to harm others when they are in a critical or dangerous situation

an air pocket, such as a bubble of air trapped in a pipe or a volume of air with different density from its surroundings

(physics) a potential well in which the motion of particles is confined to two dimensions