noun
military pact; military agreement
A formal agreement between nations concerning military cooperation, such as defense pacts or status-of-forces agreements.
両国は新たな軍事協定を結んだ。
The two countries concluded a new military pact.
軍事同盟 is a military alliance, typically implying a stronger, more binding commitment to mutual defense than a 軍事協定, which can be a narrower agreement.
Compound of 軍事 (military affairs) and 協定 (agreement, pact).