nonswan

plural nonswans

1. That which is not a swan.

   This is not translated "~s," rather, it asserts the existence of at least one nonswan, and thus becomes "~Sa."

   1968, Henry Ehlers, Logic by way of set theory, page 294

   1 more example

   Thus, faced with three instances of swans flying west to east and a nonswan (say a crow) flying east to west, an accurate inductive generalization (from this set of four instances) would be that swans fly west to east[…]

   1991, Derek Partridge, A New Guide to Artificial Intelligence, page 393