From Medieval Latin 'lavendula,' of uncertain origin — possibly from 'lavare' (to wash), as lavender scented clean linens.
An aromatic Mediterranean shrub with purple flowers, used in perfumery.
From Medieval Latin 'lavendula' or 'lavandula' (the lavender plant), of uncertain ultimate origin. The most widely accepted derivation connects it to Latin 'lavare' (to wash, to bathe), from PIE *leu(H)- (to wash, to purify), on the grounds that lavender was the standard herb used to scent bath water and laundry in the Roman world. Latin 'lavare' is the source of 'lavatory', 'laundry', 'lather', 'lave', and 'diluvian'. An alternative theory proposes the name comes from the plant's native habitat in the Ligurian Alps, from Latin 'lividus' (bluish, livid) referring to the flower's colour — the root of English 'livid'. The plant Lavandula angustifolia is native to the Mediterranean
The washing connection made lavender the herb of cleanliness.