A flanker brand is a new product introduced by a company in addition to its existing brand in a particular market category. The new flanker brand can be of a different variation (or size, type etc) of the existing brand. In essence, a flanker brand is a logical brand extension within the existing product category.
The term comes from a war metaphor as many companies use flanker brands to counter attack a competitor who challenges the existing main brand with a unique offer or proposition. So the prime focus is to position the flanker brand to counter the competitor’s offering or positioning but not disturb the main brand. Flanker brands help cater to various market segments though an inherent risk of diluting the brand image exists.
Example of a Flanker Brand: Intel introduced Centrino line of processors to protect its flagship Pentium brand when competitors were gearing up to launch lesser-priced alternatives.