any of several plants belonging to the genus Alcea (or Althaea), of the mallow family, native to Eurasia, esp. A. rosea, a tall plant having a long cluster of showy, variously colored flowers.
Origin: 1225–75; ME holihoc, equiv. to holiholy+ hoc mallow, OE hocc
hol·ly·hock (hŏl'ē-hŏk') n. A tall plant (Alcea rosea) native to the Middle East and widely cultivated for its showy clusters of very large, variously colored flowers. Also called althea.
[Middle English holihocke, marsh mallow : holi, holy; see holy + hoc, mallow (from Old English).]