mucro \MYOO-kroh, noun:

A short point projecting abruptly, as at the end of a leaf.

The outward surface of it was extremely slippery, and the mucro, or point, so very cold withal, that upon endeavoring to take hold of it, it glided through the fingers like a smooth piece of ice.
— Richard Hughes, Spectator, No. 281

Munro holds that it must be “from the mucro or point of the stylus setting a mark at each end of any length you wish to note.”
— William Ellery Leonard, De Rerum Natura

Mucro stems from Latin word mucrō meaning “sharp point.”