Webster's Revised Unabridged Dictionary
L., a claw, hoof, from unguis, a nail, claw, hoof
Chambers's Twentieth Century Dictionary
L. unguis, a nail.
Center of gravity of an ungula and semi-cylinder.
"The Mechanical Properties of Wood" by Samuel J. Record
Ungula: a hoof, claw or talon.
"Explanation of Terms Used in Entomology" by John. B. Smith