I have been smoking since I was nineteen. - On dokuz yaşımdan beri sigara içiyorum.
Nineteen states voted in the elections of 1816. - On dokuz devlet 1816 seçimlerinde oy kullandı.
The cardinal number occurring after eighteen and before twenty, represented in Roman numerals as XIX and in Arabic numerals as 19. It is the last/largest of the "teens"
[ 'on, 'än ] (preposition.) before 12th century. Middle English an, on, preposition & adverb, from Old English; akin to Old High German ana on, Greek ana up, on.