Warning: This definition may contain spoilers from any number of Games Workshop novels or source books.
Thunderhawk Gunship: An intra-system transporter and planetary attack vessel. They can be used to move troops, supplies and ammunition through short distances of space or into a planet's atmosphere. The gunships can carry approximately forty Space Marines, plus basic equipment, and are armed with a variety of cannons and missiles.
Source: Codex: Space Marines, 3rd Edition by various