Answer:
The Big Stick was the idea behind the foreign policy of former president Teddy Roosevelt. This term is an analogy of himself carrying a big stick when negotiating or establishing the terms of a multilateral relation.
Step-by-step explanation:
It means that Roosevelt would try to defend American interests abroad by any means necessary, peacefully if enough, or by force (by striking the adversary with the big stick) if necessary.
This idea relates to the Panama Canal because Roosevelt took the opportunity of supporting the indenpendence of Panama from Colombia in exchange for having a Canal built. This Canal would remain in U.S. control until the 1990s.