Word

遡る

溯る、逆上る、泝る
さかのぼる
to go upstream; to go back (in time, to origin); to date back to; to trace back to; to make retroactive
Word

遡河魚

溯河魚
そかぎょ、さっかぎょ
anadromous fish (fish that migrates upstream, e.g. salmon)
Word

遡及

溯及
さっきゅう、そきゅう
tracing back; retroactivity
Word

遡源

溯源
さくげん、そげん
returning to the origin; going back to the beginning; retracing
Word

遡行

溯航、遡航
そこう
going upstream; sailing against the current