HSK1
zài
again
Depicts catching two (二) fish at once, conveying the meaning "again". The fish component is similar to the bottom half of 冓.
二 Meaning component
èr
two
◎ Iconic component
characterless component
Depicts a fish. Similar to 冓.
Oracle script
Bronze script
Seal script
Clerical script
Regular script
再
again, twice, re-; again; once more; re-; second; another; then (after sth, and not until then); no matter how ... (followed by an adjective or verb, and then (usually) 也[yě] or 都[dōu] for emphasis)
再见
goodbye
再次
不再
no more
再说
to say again
Academia Sinica
Make Me a Hanzi
Unicode
Baxter-Sagart
Dong Chinese
CC-CEDICT
SUBTLEX-CH
MTSU Chinese text computing
漢語多功能字庫
季旭昇《說文新證》p.315-316
Wiktionary