* * *
formic acid n a colorless pungent fuming vesicant liquid acid CH2O2 found esp. in ants and in many plants and used chiefly in dyeing and finishing textiles
* * *
for·mic ac·id (forґmik) HCO2H, an acid from the distillation of ants and derivable from oxalic acid, glycerin, and the oxidation of formaldehyde. Formic acid resembles acetic acid in its actions but is far more irritating and pungent and is dangerously caustic to skin. The acid and its sodium and calcium salts are used as food preservatives.Medical dictionary. 2011.