1580s, "beak or bill of a bird," Scottish variant of neb "beak or bill of a bird." Perhaps influenced by nibble (v.). Meaning "point" (of a pen or quill) is recorded by 1610s (neb in this sense is from 1590s).
Entries linking to nib
neb n.
"beak or bill of a bird," Old English nebb "beak, nose; human face, countenance; beak-shaped thing," from Proto-Germanic nabja "beak, nose" (source also of Old Norse nef "beak, nose," Middle Dutch nebbe "beak," Old High German snabul, German Schnabel "beak," Old Frisian snavel "mouth"), which is of uncertain origin.