sid·dur (sĭdər, -r′)
n. pl. sid·du·rim (sĭ-drĭm, sĭ′d-rĭm)
A Jewish prayer book for everyday use.
[Mishnaic Hebrew siddûr, arrangement, from siddēr, to arrange, derived stem of sādar; see sdr in the Appendix of Semitic 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.