Is it ensure, insure, or assure?
aromatic shrubby plant, early 15c., from Old French basile (15c., Modern French basilic), from Medieval Latin basilicum, from Greek basilikon (phyton) "royal (plant)," from basileus "king" (see Basil). So called, probably, because it was believed to have been used in making royal perfumes. In Latin, confused with basiliscus (see basilisk) because it was supposed to be an antidote to the basilisk's venom.
masc. proper name, from Latin Basilius, from Greek Basileios "kingly, royal," from basileus "king," of unknown origin, possibly from a language of Asia Minor (cf. Lydian battos "king").