foretriangle Syllabification: (fore·tri·an·gle)Pronunciation: /ˈfôrˌtrīˌaNGgəl/Definition of foretriangle noun the triangular space between the deck, foremast, and forestay of a sailing vessel. the area of sail within the foretriangle. foretriangle in other Oxford dictionaries Definition of foretriangle in the British & World English dictionary