Why was "tantrum" trending last week?
early 14c., from Old French panel "piece of cloth, piece, saddle cushion" (Modern French panneau), from Vulgar Latin *pannellus, diminutive of Latin pannus "piece of cloth" (see pane). Anglo-French legalese sense of "piece of parchment (cloth) listing jurors" led by late 14c. to meaning "jury." General sense of "persons called on to advise, judge, discuss," etc. is from 1570s. Sense of "distinct part of surface of a wall, door, etc." is first recorded c.1600.
in architecture and design, decorative treatment of walls, ceilings, doors, and furniture consisting of a series of wide, thin sheets of wood, called panels, framed together by narrower, thicker strips of wood. The latter are called styles (the external vertical strips), muntins (the internal vertical strips), and rails (the horizontal strips).