a. A period of seven days: a week of rain.
b. A seven-day calendar period, especially one starting with Sunday and continuing through Saturday: this week.
a. A week designated by an event or holiday occurring within it: commencement week.
b. A week dedicated to a particular cause or institution: Home Safety Week.
3. The part of a calendar week devoted to work, school, or business: working a three-day week.
a. One week from a specified day: I'll see you Friday week.
b. One week ago from a specified day: It was Friday week that we last met.
[Middle English weke, from Old English wicu; see weik-2 in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.