The Chinese word 洪水 is analysed below into its constituent words and the words into radicals. By seeing the breakdown of the word in this way you can more easily learn and recognise the word.
1. n. flood
洪水 ⇨ 洪 + 水
1. vast, immense
2. flood, deluge
洪 ⇨ 氵 + 共
3. to share
共 ⇨ 龷 + 八
1. an accounting version of the numeral eight that is otherwise written astr=-
2. usage. Minor strokes in the shape of ハ/八, as in the top of 劵, can be referred to 八. These are very frequently simplified to 丷. Contrast 劵/券, and different forms of (lang, ja, 鬲)/lang, und, sc=Hans, 鬲.
3. (zh-alt-form, 朳, toothless rake)
5. (zh-alt-form, 扒, to break open, split open)
6. many, numerous
7. to know; to recognise; to be familiar with
8. (printing) pearl; The smallest size of usual type, standardized as 5 point.