Definition of "subfamily" [sub•fam•i•ly]

• Biology A taxonomic category of related organisms ranking between a family and a genus. (noun)
• Linguistics A division of languages below a family and above a branch. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "On the origins of Hippopotamidae together with descriptions of two species, a new genus and a new subfamily from the Miocene of Kenya."
• "In the era immediately following World War II, the subfamily was a convenient startup arrangement for young couples newly married and as a residential arrangement for an elderly dependent parent in the home of a son or daughter."
• "Most cool season cereal, forage and turf grasses belong to the Pooideae subfamily, which is also the largest grass subfamily."