The term Regalian was used in the late 24th century to denote various items and ideas.
The various Regalian items likely originate from a Regalian planet or species.
Captain Jean-Luc Picard studied Regalian law. (TNG: "Final Mission")
The Gatherers were in possession of phaser rifles of a Regalian origin. (TNG: "The Vengeance Factor")
Quark imported some fleaspiders and liquid crystals together. Both were denoted as Regalian. (DS9: "The Ship")