1. A succession of organisms in an ecological community that constitutes a continuation of food energy from one organism to another as each consumes a lower member and in turn is preyed upon by a higher member.
2. Informal. A competitive hierarchy: "was reduced to character roles while struggling to defend his position in the Hollywood food chain" (Kathryn Shattuck).

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.