All of the above, and a class of space-faring large warships, probably cruiser/destroyers in Bungie's FPS Halo. The one and only known Halcyon-class ship is the Pillar of Autumn, under the command of Capt. Jacob Keyes.

Not all too much is known about its equipment, but from what we know,
* it houses a whole lot of Marines (probably above a thousand)
* it has a four-rod nuclear (probably fusion) reactor
* it has an incredibly powerful AI called Cortana, but an immensely and unusually small bridge (one captain, 3 helmsmen, 3 navigators, 4 other personnel)
* it has a cryo facility
* oh, and it has a bay loaded with 4 Pelicans (dropships), one of them called Foe-Hammer.