| Acid (a.) Sour, sharp, or biting to the taste |
| Acid (a.) Of or pertaining to an acid |
| Acid (n.) A sour substance. |
| Acid (n.) One of a class of compounds, generally but not always distinguished by their sour taste, solubility in water, and reddening of vegetable blue or violet colors. They are also characterized by the power of destroying the distinctive properties of alkalies or bases, combining with them to form salts, at the same time losing their own peculiar properties. They all contain hydrogen, united with a more negative element or radical, either alone, or more generally with oxygen, and take their names from this negative element or radical. Those which contain no oxygen are sometimes called hydracids in distinction from the others which are called oxygen acids or oxacids. |
| Barbituric acid () A white, crystalline substance, CH2(CO.NH)2.CO, derived from alloxantin, also from malonic acid and urea, and regarded as a substituted urea. |
| Cyanuric acid () an organic acid, C3O3N3H3, first obtained by heating uric acid or urea, and called pyrouric acid |
| Monte-acid (n.) An acid elevator, as a tube through which acid is forced to some height in a sulphuric acid manufactory. |
| Salso-acid (a.) Having a taste compounded of saltness and acidity |
| acetic acid / ethanoic acid a colorless pungent liquid widely used in manufacturing plastics and pharmaceuticals |