Jisho (辞書)
Jisho is a CLI tool & Rust library that provides offline access to EDICT, the excellent machine-readable Japanese-English dictionary project originally started by Jim Breen.
Use
$ jisho 辞書
辞書【じしょ】- dictionary
$ jisho "quantum mechanics"
量子力学【りょうしりきがく】- quantum mechanics