9 (number)

← 8 9 10 →
-1 0 1 2 3 4 5 6 7 8 9 → List of numbers — Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	nine
Ordinal	9th (ninth)
Numeral system	nonary
Factorization	32
Greek numeral	Θ´
Roman numeral	IX
Unicode symbol(s)	Ⅸ, ⅸ
Greek prefix	ennea-
Latin prefix	nona-
Binary	10012
Ternary	1003
Quaternary	214
Quinary	145
Senary	136
Octal	118
Duodecimal	912
Hexadecimal	916
Vigesimal	920
Base 36	936
Amharic	፱
Arabicl	٩
Urdu
Armenian numeral	Թ
Bengali	৯
Chinese/Japanese /Korean numeral	九 (jiu) 玖 (formal writing)
Devanāgarī	९ (Nao)
Greek numeral	θ´
Hebrew numeral	ט (Tet)
Tamil numeral	௯
Khmer	៩
Telugu numeral	౯
Thai numeral	๙

The Simple English Wiktionary has a definition for: nine.

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9 (nine) is the Arabic number which comes after 8 and before 10. It is an odd number, and is the highest single-digit number. It is also a square number. In Roman numerals, nine can be written as IX.

The number also looks like an inverted 6. To tell the difference between the two, they are often underlined.