trigonePronunciation: /trɪˈgəʊn, ˈtrʌɪ-/Definition of trigone noun Anatomy a triangular region or tissue, particularly the area at the base of the urinary bladder, between the openings of the ureters and urethra. Origin: mid 19th century: from French, from Latin trigonum 'triangle'trigone in other Oxford dictionaries Definition of trigone in the US English dictionary