laugh·line or laugh line (lăflīn′, läf-)
1. A lasting wrinkle formed at the outer corner of the eye or along the side of the mouth, especially noticeable when one laughs or smiles.
2. A line of dialogue intended to cause laughter: "actors who are directed ... to cutely underline every nuance and laughline" (Laurie Winer).
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.