fil·i·al (fĭlē-əl, fēlē-)
1. Of, relating to, or befitting a son or daughter: filial respect.
2. Having or assuming the relationship of child or offspring to parent.
3. Genetics Of or relating to a generation or the sequence of generations following the parental generation.
[Middle English, from Old French, from Late Latin fīliālis, from Latin fīlius, son; see dhē(i)- 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.