The number 9. It comes after eight and before ten.

Ordinal: ninth (the 'e' is dropped: nine → ninth). Common collocations: nine-to-five (working hours), dressed to the nines (dressed very smartly), a stitch in time saves nine (proactive action prevents bigger problems).

'Dressed to the nines' means dressed very elegantly and smartly. 'A stitch in time saves nine' is a proverb meaning that fixing a small problem early prevents it from becoming a bigger one. A cat is said to have nine lives in English folklore.