n. pl. di·a·ries
a. A usually daily written record of personal experiences and observations; a journal.
b. A daily record of events or measurable phenomena, usually kept to track patterns over time: kept a diary of blood sugar levels.
2. A book or computer file used for keeping such a record.
[Latin diārium, daily allowance, daily journal, from diēs, day; see dyeu- in the Appendix of Indo-European roots.]
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.