also: ざんさい
noun, noun which may take the genitive case particle 'no'
remains; dregs; vestiges; remnant; residue
Refers to what is left behind after something has been removed, filtered, or has passed; can be physical residue, dregs, or figurative remnants of a past era or system.
コーヒーの残滓がカップの底にたまっていた。
Coffee dregs had collected at the bottom of the cup.
その制度は封建時代
That system is said to be a vestige of the feudal era.
Compound of 残 (remain) and 滓 (dregs, sediment). The reading ざんし is the standard on'yomi; ざんさい is an alternative reading of the second character.