quintessence

noun

1 Wemmick's cottage is the quintessence of the Victorian home:

perfect example, exemplar, prototype, stereotype, picture, epitome, embodiment, personification, paragon, ideal;

best, cream, elite, flower, jewel, gem, pick, prime, last word, acme of perfection;

French crème de la crème, beau idéal.

2 they wanted to know how our brains function and thereby discover the quintessence of intelligence:

essence, soul, spirit, ethos, nature, core, heart, centre, crux, nub, nucleus, kernel, marrow, pith, substance, sum and substance;

informal nitty-gritty;

Philosophy quiddity, esse.

quintessence Oxford Dictionary of English