1. A black pool ball that bears the number eight.
2. A game in billiards played with a cue ball and 15 object balls in which the winner must pocket the eight ball after pocketing the seven balls numbered either higher than or lower than the eight ball, with the requirement that the cue ball must first strike one of the seven balls allotted to a player for a shot to be legitimate. A player who pockets the eight ball before the other seven automatically loses.
behind the eight ball Slang
In an unfavorable or uncomfortable position.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.