pinxit
An inscription indicating the identity of the one who created a painting.
A potential buyer of The Princess had refused to purchase unless Whistler modified his pinxit, scrawled across a corner of the canvas.
Where it comes from
From the appearance of the Latin word pinxit (“he/she painted (this)”), perfect indicative third-person singular of pingo (“to paint”), after a painter's name on a painting.
Adapted from the Wiktionary entry pinxit (CC BY-SA 4.0).