ox·a·lis (ŏk'sə-lĭs, ŏk-sāl'ĭs) n. Any of numerous plants of the genus Oxalis, having often cloverlike compound leaves with three leaflets and variously colored flowers that are usually clustered in umbels. Also called wood sorrel.
[Latin oxalis, wood sorrel, from Greek, from oxus, sour; see ak- in Indo-European roots.]