Definition of "extancy"

[W]hereas in ſmall fragments or plates, the Ice, though it ſink not to the bottom of the water, will oftentimes ſink so low in it, as ſcarce to leave any part evidently extant above the ſurface of the water, in vaſt quantities of Ice, that extancy is ſometimes ſo conſpicuous, that Navigators in their Voyages to Iſland, Greenland, and other frozen Regions, complain of meeting with lumps, or rather floating rocks of Ice, as high as their main Maſts.

1663, Robert Boyle, “Title IX. Experiments in Consort, Touching the Bubbles from which the Levity of Ice is Supposed to Proceed.”, in New Experiments and Observations Touching Cold, or, An Experimental History of Cold, Begun. […], London: […] Richard Davis, […], published 1683, paragraph 1, page 95

Moreover, a perfect Medal has its Profile and out-ſtroaks ſharp (Nummus aſper) and by no means rugged; the Figures clean and well poliſh'd; the Contours neatly trimm'd, and exactly round and carefully preſerv'd; that the Extancy and Relievos correſpond with the Ingraving, and have not ſuffer'd in Percuſſion; in all which, there is a certain Spirit of Antiquity and Excellency to be diſcern'd in Antient Medals almoſt inimitable.

1697, J[ohn] Evelyn, “Instructions How to Collect, and Procure such Medals as are Antique, and Rare; and to Distinguish the True from the False, for the Prevention of Frauds and Impostures”, in Numismata. A Discourse of Medals, Antient and Modern. […], London: […] Benj[amin] Tooke […], page 201