• (British) IPA: /trɪˈɡəʊn/, /ˈtrʌɪɡəʊn/

trigone (plural trigones)

1. (botany) One of the thickenings of the cell wall at the angles where several cells join.
   • 1992, Marie L. Hicks, Guide to the Liverworts of North Carolina, page 66

     Leaf cells are about 25–30 μm, with thin walls and bulging trigones.

   • 1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, New York, N.Y.: Columbia University Press, →ISBN, page 4-5:

     The epidermal cells of the capsule wall of Jubulopsis, with nodose "trigones" at the angles, are very reminiscent of what one finds in Frullania spp.

2. (anatomy) A smooth triangular area on the inner surface of the bladder, bounded by the apertures of the ureters and urethra; a similar region of a mitral valve

• trigonal