a parasitic nematode, Dirofilaria immitis, transmitted by mosquito and invading the heart and pulmonary arteries of dogs, wolves, and foxes throughout its range in tropical, subtropical and, more recently, temperate regions around the world.
the disease caused by infection with heartworm.

Origin of heartworm

First recorded in 1885–90; heart + worm
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for heartworm

Historical Examples of heartworm

  • In France it is called le ver du cœur (the heartworm), because it penetrates in between leaves pressed closely together.

    The Insect World

    Louis Figuier

British Dictionary definitions for heartworm



a parasitic nematode worm, Dirofilaria immitis, that lives in the heart and bloodstream of vertebrates
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012