Sidearm

Sidearms in the Halo Universe are a class of weapons that play both a primary and secondary role in combat.

List of Sidearms and their strength

 * M6 Pistol (GoO: Unknown)
 * M6D Pistol (Halo: very Strong)
 * M6C Magnum (Halo 2 (Pre-Update): Average / Halo 2 (Post-Update): Weak)
 * M6B Pistol (GoO: Unknown)
 * M6G Magnum (Halo 3: Average)
 * Energy Sword (Halo 2: Strong / Halo 3: Very Strong)
 * Needler (Halo: Average / Halo 2: Average / Halo 3: Strong)
 * Plasma Rifle (Halo: Strong / Halo 2: Weak / Halo 3: Average)
 * Brute Plasma Rifle (Halo 2: Average)
 * Plasma Pistol (Halo: Average / Halo 2: Very Weak / Halo 3: Average)
 * Brute Spiker (Halo 3: Average)

Modern definition
A sidearm is a small personal weapon that is typically worn on the body in a holster in such a way to permit immediate access and use. Although this term can apply to swords and other melee weapons, the modern use of it is usually affiliated with pistols and similar firearms that can be used with ease, most only requiring one hand.