The ordinal form of the number eleventeen.(adjective)
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Use "eleventeenth" in a sentence
"After consulting numerous websites, I've self-diagnosed myself with the eleventeenth variety of terminal cancer that's afflicted me ever since I could first Google disease in 1999."
"But a quick try to view www.edballs.com/robots.txt produces this response from eleventeenth Ltd: deliberate lower case "e"!"
"This was, as Gammy would say, “the eleventeenth hour.”"