| 2025-06-30 | Base that dissolves in water |
| 2021-11-22 | Corrosive substance |
| 2021-03-10 | Acid's opposite |
| 2020-01-31 | Lye, for one |
| 2019-10-30 | High-pH compound |
| 2017-05-09 | High-pH substance |
| 2016-06-02 | Any element in the first column of the periodic table, except hydrogen |
| 2016-05-22 | Basic material |
| 2015-11-09 | ___ metals (periodic table group) |
| 2014-11-07 | Basic thing |
| 2013-11-10 | Base |
| 2012-05-18 | Lye, for one |
| 2011-07-18 | Soluble salt mixture |
| 2009-01-18 | Basic stuff |
| 2008-05-14 | Lye, e.g. |
| 2007-01-31 | It's basic |
| 2003-05-13 | Acid-neutralizing compound |
| 2003-04-27 | Acid neutralizer |
| 2002-05-09 | Potassium hydroxide is one |
| 2002-01-20 | Acid neutralizer |
| 2001-12-23 | Soluble mineral salt |
| 2001-06-28 | Acid neutralizer |
| 2000-09-17 | Acid neutralizer |
| 2000-02-29 | Acid neutralizer |
| 1999-08-08 | Poor soil ingredient |
| 1997-09-29 | Acid neutralizer |
| 1996-01-21 | Base |