adjective
1. being or containing an acid; of a solution having an excess of hydrogen atoms (having a pH of less than 7)
• Ant: ↑alkaline, ↑amphoteric
• Similar to: ↑acid, ↑acid-forming
• Topics: ↑chemistry, ↑chemical science
2. being sour to the taste
• Similar to: ↑sour
• Derivationally related forms: ↑acidulousness (for: ↑acidulous)
Useful english dictionary. 2012.