The American Heritage® Dictionary of the English Language: Fourth Edition. 2000.
Appendix I
Indo-European Roots
ENTRY:
nogh-
DEFINITION:
Also ongh-. Nail, claw. Oldest forms *3nogh-, *3ongh-.1. Suffixed (diminutive) form *nogh-elo-.nail, from Old English nægl, nail, from Germanic *nagla-.2. Form *nogh-.onyx; paronychia, perionychium, sardonyx, from Greek onux (stem onukh-), nail. 3. Variant form *ongh-.unguiculate, unguis, ungulate, from Latin unguis, nail, claw, hoof, with diminutive ungula, hoof, claw, talon (< *ongh-el-). (Pokorny onogh- 780.)