The American Heritage Dictionary of the English Language

The American Heritage Dictionary of the English Language (AHD) is a dictionary of American English published by HarperCollins. As of 2025 it is in its fifth edition.
Before HarperCollins acquired certain business lines from Houghton Mifflin Harcourt in 2022, the family of American Heritage dictionaries had long been published by Houghton Mifflin Harcourt and its predecessor Houghton Mifflin. The first edition appeared in 1969, an outgrowth of the editorial effort for Houghton Mifflin's American Heritage brand of history books and journals.