lit. source is distant and the flow is long (成语 saw); fig. sth goes back to the dim and distant past; a lot of water has flowed under the bridge since then[cedict]
的
deㄉㄜ˙
díㄉㄧˊ
dìㄉㄧˋ
of; structural particle: used before a noun, linking it to preceding possessive or descriptive attributive[cedict]