Ŏx-ăl'ic, a.

a. [Fr. oxalique, from Lat. oxalis, Gr. ὀξαλίς, a sort of sorrel, from ὀξύς, sharp, pungent, acid.] Pertaining to, contained in, or obtained from, sorrel.

Oxalic acid, an acid found in many plants, to which it gives a sourish taste, as the wood-sorrel (Oxalis acetosella), and many lichens. It is very poisonous in large doses. This acid is prepared chemically for various uses. Under the name of salt of lemons, it is used to remove ink spots, iron rust, &c.