Though officially no rivalries exist between Appleby College and other schools, Ridley College in St. Catharines, Ontario is often viewed as a potent rival of the Blue Dogs.

Mr. Bush's advisers say they are not rattled now that they are threatened by a potent rival.

It is also a business that is a potentially potent future rival to Mr. Malone's own cable industry.

Brown intended to use alternating current (AC), then emerging as a potent rival to direct current (DC), which was further along in commercial development.

In particular, Mr. Dauman had emerged as a potent rival to Mr. Biondi.

The loss is a blow to Microsoft, which had sought AOL as a partner in its advertising venture to undercut Google, its potent rival.

Growing Financial Influence Because of Germany's growing financial influence, Frankfurt is viewed among banks and investment houses here as the most potent rival.

Mr. McCain, who has emerged as a potent rival to Mr. Bush in New Hampshire, trumpeted his prescriptions to reform the campaign finance system.

Even so, voters said they considered Mr. Bush more of a leader - and a more potent rival against the Democrats in November.

Now its main Web search results are provided by Google, which has become Yahoo's most potent rival in online search advertising.