| Answer | Crossword Clue |
|---|---|
| EURO | Widely used money |
| DUCATS | Widely accepted medieval money |
| ETC | Widely used abbr. |
| EURO | Widely used currency |
| TEN | Widely used base |
| UNIX | Widely used operating system |
| ONOFF | Widely used switch type |
| UNIX | Widely used computer operating system |
| PROLOG | Language widely used in artificial intelligence applications |
| PABA | UV filter once widely used in sunscreens |
| IRONORE | Source of the most widely used metal |
| POPEMOBILE | Widely used term declared "undignified" by John Paul II |
