Толковый словарь английского языка Oxford English Reference - eleventh

n. & adj. --n. 1 the position in a sequence corresponding to the number 11 in the sequence 1-11. 2 something occupying this position. 3 one of eleven equal parts of a thing. 4 Mus. a an interval or chord spanning an octave and a third in the diatonic scale. b a note separated from another by this interval. --adj. that is the eleventh. Phrases and idioms the eleventh hour the last possible moment.