bond paper

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

• noun A superior grade of strong white paper made wholly or in part from rag pulp.

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

• noun A high-quality durable writing paper similar to bank paper but of greater weight, formerly used for government bonds.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a superior quality of strong durable white writing paper; originally made for printing documents