If you receive a Error Code, that means that something has gone wrong while you are playing Destiny. Some frequent error codes include:
Canary
Carp
Caribou
Buzzard/Vulture
Bull
Beagle
Caterpillar
Buck/Camel/Cattle
Centipede
Pear
Urchin
Cat
Marionberry
Blackbird/Chipmunk/Lime
Butterfly/Stingray