In Mandarin Chinese, 八 (Pinyin: bā 🔊) is a word for “eight”. It is considered a lucky number, because its pronunciation is similar to that of 發 / 发 (fā), which means “to make a fortune”. You may have heard or seen this latter word in the traditional New Year greeting, 恭喜發財 / 恭喜发财 (gōngxǐ fācái), literally “Congratulations, (may you) become wealthy”.
The original meaning of 八 was “to divide”. I don’t think the ancient Chinese knew much about cell division but somehow most historical forms of this character remind me of a pair of chromosomes.
The Chinese hand sign for “eight” is a hand with the thumb and index finger at a right angle and the other fingers closed:
There is another hanzi with the same meaning, 捌, which is mainly used for financial purposes.