| Number: | 8 |
| Numeral: | octal |
| Divisor: | 1, 2, 4, 8 |
| Roman: | VIII, viii |
| Greek Prefix: | octa-/oct- |
| Latin Prefix: | octo-/oct- |
| Lang1: | Greek |
| Lang1 Symbol: | η (or Η) |
| Lang2: | Arabic, Kurdish, Persian, Sindhi, Urdu |
| Lang3: | Amharic |
| Lang3 Symbol: | ፰ |
| Lang4: | Bengali |
| Lang5: | Chinese numeral |
| Lang5 Symbol: | 八,捌 |
| Lang6: | Devanāgarī |
| Lang7: | Kannada |
| Lang8: | Malayalam |
| Lang9: | Telugu |
| Lang10: | Tamil |
| Lang11: | Hebrew |
| Lang12: | Khmer |
| Lang12 Symbol: | ៨ |
| Lang14: | Thai |
| Lang14 Symbol: | ๘ |
| Lang15: | Armenian |
| Lang15 Symbol: | Ը ը |
| Lang16: | Babylonian numeral |
| Lang17: | Egyptian hieroglyph |
| Lang19: | Morse code |
| Cardinal: | eight |
8 (eight) is the natural number following 7 and preceding 9.
English eight, from Old English , æhta, Proto-Germanic *ahto is a direct continuation of Proto-Indo-European
-, and as such cognate with Greek Greek, Ancient (to 1453);: ὀκτώ and Latin, both of which stems are reflected by the English prefix oct(o)-, as in the ordinal adjective octaval or octavary, the distributive adjective is octonary.The adjective octuple (Latin) may also be used as a noun, meaning "a set of eight items"; the diminutive octuplet is mostly used to refer to eight siblings delivered in one birth.
The Semitic numeral is based on a root *θmn-, whence Akkadian smn-, Arabic ṯmn-, Hebrew šmn- etc.The Chinese numeral, written Chinese: 八 (Mandarin: bā; Cantonese: baat), is from Old Chinese *priāt-, ultimately from Sino-Tibetan b-r-gyat or b-g-ryat which also yielded Tibetan brgyat.
It has been argued that, as the cardinal number is the highest number of items that can universally be cognitively processed as a single set, the etymology of the numeral eight might be the first to be considered composite, either as "twice four" or as "two short of ten", or similar.The Turkic words for "eight" are from a Proto-Turkic stem *sekiz, which has been suggested as originating as a negation of eki "two", as in "without two fingers" (i.e., "two short of ten; two fingers are not being held up");[1] this same principle is found in Finnic
, which conveys a meaning of "two before (ten)". The Proto-Indo-European reconstruction
- itself has been argued as representing an old dual, which would correspond to an original meaning of "twice four".Proponents of this "quaternary hypothesis" adduce the numeral , which might be built on the stem new-, meaning "new" (indicating the beginning of a "new set of numerals" after having counted to eight).[2]
The modern digit 8, like all modern Arabic numerals other than zero, originates with the Brahmi numerals.The Brahmi digit for eight by the 1st century was written in one stroke as a curve └┐ looking like an uppercase H with the bottom half of the left line and the upper half of the right line removed.However, the digit for eight used in India in the early centuries of the Common Era developed considerable graphic variation, and in some cases took the shape of a single wedge, which was adopted into the Perso-Arabic tradition as ٨ (and also gave rise to the later Devanagari form ८); the alternative curved glyph also existed as a variant in Perso-Arabic tradition, where it came to look similar to our digit 5.
The digits as used in Al-Andalus by the 10th century were a distinctive western variant of the glyphs used in the Arabic-speaking world, known as ghubār numerals (ghubār translating to "sand table"). In these digits, the line of the 5-like glyph used in Indian manuscripts for eight came to be formed in ghubār as a closed loop, which was the 8-shape that became adopted into European use in the 10th century.[3]
Just as in most modern typefaces, in typefaces with text figures the character for the digit 8 usually has an ascender, as, for example, in .
The infinity symbol ∞, described as a "sideways figure eight", is unrelated to the digit 8 in origin; it is first used (in the mathematical meaning "infinity") in the 17th century, and it may be derived from the Roman numeral for "one thousand" CIƆ, or alternatively from the final Greek letter, ω.
Eight is the third composite number, lying between the fourth prime number (7) and the fourth composite number (9). 8 is the first non-unitary cube prime of the form p3. With proper divisors,, and, it is the third power of two (2). 8 is the first number which is neither prime nor semiprime and the only nonzero perfect power that is one less than another perfect power, by Mihăilescu's Theorem.