From Longman Dictionary of Contemporary Englishnibnib /nɪb/ noun [countable] 1 
DTthe pointed metal part at the end of a pen2 → his/her nibs
DTthe pointed metal part at the end of a pen2 → his/her nibsExamples from the Corpus
nib• The forefinger of this was capped with a golden nib!• The quill nib produces a crisper line as a result.• Plus a recess above the nibs allows the tiles to be stacked virtually flat.• I apply the paint to the nib with a brush.• The nib allows for greater speed and directness of drawing.• They used pens with nibs and it was a trouble not to blot the page.Origin nib (1500-1600) Probably from neb “beak” ((11-19 centuries)), from Old English nebb 