The story
Coined by James Dalgety in 1990, from the puzzle inventor's name (Non Ishida) and diagram.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A puzzle in which cells of a grid must be filled or left blank, according to sets of numbers given at the side of the grid, to reveal a hidden picture. Full definition →
Coined by James Dalgety in 1990, from the puzzle inventor's name (Non Ishida) and diagram.
Etymology from Wiktionary, CC BY-SA 4.0.