an herb (Nepeta cataria) of the mint family, with downy leaves and spikes of white or bluish flowers that are used in flavorings and tea: cats like its odor
See catnip in American Heritage Dictionary 4
(kătˈnĭpˌ)
noun
A hairy aromatic perennial herb (Nepeta cataria) in the mint family, native to Eurasia and containing an aromatic oil to which cats are strongly attracted.
Any of various other mostly aromatic plants of the genus Nepeta, cultivated for their ornamental foliage and clusters of blue, lavender, or white flowers.