space suit

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A protective pressure suit designed to permit the wearer relatively free movement in space.

from the GNU version of the Collaborative International Dictionary of English.

• noun a protective suit covering the whole body, completely airtight and designed to withstand internal pressure, worn by astronauts to protect them from the vacuum and other hazards of outer space. It typically contains an air supply and other life-support equipment to allow functioning independent of any other equipment for a period of time while in space.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A system of protective and pressurized clothing, together with environmental equipment, worn by astronauts when in space