Definition of bluet
- a low-growing North American plant of the bedstraw family, with small four-petaled flowers and paired leaves. Bluets often grow in large groups.
- Genus Houstonia (or Hedyotis), family Rubiaceae: several species, especially H. caerulea, with milky-blue or white flowers, and long-leaved bluets (H. longifolia), with white or lavender flowers
early 18th century: from French, diminutive of bleu 'blue'