Related Clues:

• Word with "rain" or "test"
• Biting — tart
• Acetic, for one
• Word before rain or test
• __ test
• Sulfuric ___
• Stereo jack label
• Nitric ___
• Etching stuff
• It's not basic
• Need for 41-Across
• Biological food processor
• Liquid that can eat through metal
• ___ rock
• 4-Down's item