Meaning

noun the idea of something that is perfect; something that one hopes to attain

noun model of excellence or perfection of a kind; one having no equal

adjective conforming to an ultimate standard of perfection or excellence; embodying an ideal

originFrom French idéal, from Late Latin ideālis (“existing in idea”), by surface analysis, idea + -al, from Latin idea (“idea”); see idea. In mathematics, the noun ring theory sense was first introduced by German mathematician Richard Dedekind in his 1871 edition of a text on number theory. The concept was quickly expanded to ring theory and later generalised to order theory. The set theory and Lie…

Etymology from Wiktionary, CC BY-SA 3.0