Meaning of Y in English

(AMOUNT NOT STATED) [noun] [U] - used to represent the second of two numbers or names which are not known or stated when the first is represented by 'x'If 2x = 3y and x=6, then y=4.The children on trial, known as child X and child Y, were accompanied by their parents. -y (QUALITY) [suffix] - added to nouns to form adjectives meaning like the stated thinginkycheesy

Cambridge English vocab.      Кембриджский английский словарь.