hyssop n.

Old English ysope, from Irish Latin hysopus (Medieval Latin ysopus), from Greek hyssopos, a plant of Palestine, used in Jewish purification rites, from Hebrew 'ezobh (compare Syriac zupha, Arabic zufa). Since Old English the word has been used both of a small, bushy, aromatic herb native to southern Europe and the Biblical hyssop, a different plant, used in purification rituals, variously identified.