Nail (anatomy)
A nail was a covering of keratin on the end of one's digits (fingers or toes).

Fingernail 

According to Doctor Phlox, germs could survive almost anywhere, even under a fingernail. ()

In 2259 of the alternate reality,  wore polish on her fingernails that matched the color of her sciences division uniform. ()

In 2269, while inhabiting the body of James T. Kirk, Janice Lester filed his fingernails. ()

A microscopic generator hidden under his fingernail enabled Rao Vantika to transfer his consciousness to Doctor Julian Bashir in 2369. ()

In 2371, Jadzia Dax chided her former fellow host of the  symbiont Tobin Dax for biting Chief Miles O'Brien's s while speaking through his body for Jadzia's zhian'tara. Tobin apologized, saying he was nervous. ()

Toenail 

Denobulans had colored long toenails. ()

See also 
 Hangnail
 Ingrown toenail

External link 
 

de:Fingernagel
Anatomy