The term "seventeenth" refers to the ordinal number that comes after sixteenth and before eighteenth. It is used to indicate the position of something in a sequence, such as the seventeenth day of the month or the seventeenth chapter of a book. In mathematics, the number 17 is significant as it is a prime number, meaning it can only be divided by 1 and itself. In various cultures, the number 17 may hold special meanings or significance, such as in numerology or astrology.