: a perennial composite (see compositeentry 1 sense 1b) herb (Chamaemelum nobile synonym Anthemis nobilis) of Europe and North Africa with aromatic (see aromaticentry 1 sense 1) foliage and flower heads
2
: any of several composite plants (genera Matricaria and Anthemis) related to chamomile
especially: an annual Eurasian herb (M. recutita synonym M. chamomilla) naturalized (see naturalizesense 4) in North America
3
: the dried flower heads of chamomile that are often used in making tea and that yield an essential oil possessing medicinal properties