1. One that terminates: a terminator of unpopular policies.
2. The dividing line between the bright and shaded regions of the disk of a moon or planet that is illuminated by the sun.
3. A sequence of nucleotides that signals the end of transcription or translation and the completion of the synthesis of a nucleic acid or protein molecule.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.