First strike and First-strike

First strike noun - The initial use of nuclear weapons to attack a country that also has nuclear weapons; considered feasible only when the attacker can destroy the other country's ability to retaliate.

First-strike and first strike are semantically related. In some cases you can use "First-strike" instead an adjective phrase "First strike".

First strike and first-strike are semantically related. Sometimes you can replace phrase "First strike" with "First-strike", this phrases are similar.