Meaning

noun any of various plants of the genus Althaea; similar to but having smaller flowers than genus Alcea

noun any of various tall plants of the genus Alcea; native to the Middle East but widely naturalized and cultivated for its very large variously colored flowers

originFrom Middle English holihocke, holyhokke, holihoc, from holi (“holy”) + hocke, hokke, hoc (“mallow”) (from Old English hoc (“marsh mallow”). The modern hollyhock was probably unknown in England until the 15th century, so usage before then no doubt referred to some other mallow. Apparently so called for being brought from the Holy Land; compare an old name for it in Medieval Latin cauli Sancti…

Etymology from Wiktionary, CC BY-SA 3.0