Terra is the latin name for Earth. The planet we humans currently enhabit. Also in the fantacy wargame called "Warhammer 40 000" Terra is the name of the capital planet from whitch the Emperor of Mankind rules the Imperium.
Space Marine battle cry: "FOR TERRA! FOR THE EMPEROR!"
1R21337 means "I are too leet" whitch in laymans terms means "I am too awsome". This is a phrase writen in "1337" speak and is often used by nerds, hakers (hate thoughs fuckers), halo fans, and people of the like.
A very large and near impregnible suit of aurmor worn by space marines (warhammer 40k universe). This suit has a thermo nuclear power pack whitch gives it its name, Power Suit. more simply its like a midevil suit of armour but it has hydrolic and phumatic joints, nero interface, built in Vox communicator, ect. Also this suit is made of a imaginary super metal called Adimantium whitch is like a super titanium/iron substance.
....and to complete the marine he was granted the awsome power suit to wear into battle.