mutual fund

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

• noun An investment company that continually offers new shares and buys existing shares back at the request of the shareholder and uses its capital to invest in diversified securities of other companies.

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

• noun finance A form of collective investment in which money from many investors is pooled and invested in stocks, bonds, short-term money market instruments, and/or other securities under the direction of a fund manager.

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

• noun a regulated investment company with a pool of assets that regularly sells and redeems its shares
• noun the pooled money that is invested in assets