nymphs who were the daughters of Atlas and Pleïone (or Atlas and Hesperis, or even Erebus and Nyx), and who were the 'Daughters of the Evening' or 'Nymphs of the West'.
They lived on an island in the west of the ocean and guarded the garden with golden apples that Gaia had given to Hera on her marriage to Zeus. They vary in number, depending on the source, but usually settle to four or seven. Originally, however, there were only three, who were Aegle, Erythea and Hespera. Later Hesperides were Arethusa, Hestia, Hesperusa and Hesperia.
Of these, four names immediately and obviously relate to the collective name, which in turn simply comes from hespera, 'evening', 'west'. (There is even, etymologists tell us, a link between the Greek word - and the nymphs' name - and English 'west'.) The golden apples are significant in this, of course, since an apple, especially a ripe or ripening one, is the colour of the setting sun - red, yellow or gold.