thirteener UK /θɜːˈtiːnə/US /θɜɹˈtinəɹ/ noun7 •A child who is thirteen years old. •(US) A mountain rising to more than 13,000 feet (about 4,000 metres) but less than 14,000 feet above mean sea level.Few who venture into this region know that the area is a superb place to go after thirteener ski descents. — 2020 •The last playing card of a suit left after the other twelve have been played. •(old-fashioned) A member of the 13th Gen; a Generation Xer or Gen-Xer. •A thirteen-syllable line or series of lines in a poem.[T]he peculiar Latin thirteener so popular in the Middle Ages, and best known by the lines attributed to Mapes—Meum est propositum in taberna mori [My purpose is to die in a tavern]. — 1910 •A hit for thirteen runs. •(old-fashioned) A coin worth thirteenpence, especially an Irish shilling (as contrasted with a British shilling which was worth twelvepence). formsthirteeners