Something that is intricate or convoluted like a labyrinth and often has no outlet or resolution: “She was plunged down a rabbit hole of benefits changes, paperwork deadlines, ... insurance payoffs, and financial decisions” (Kristin Henderson).
[From the rabbit hole in Alice's Adventures in Wonderland by Lewis Carroll, after entering which Alice encounters bizarre characters and situations impeding her escape.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.