From the Greek erasthai, refers to the part of love constituting a passionate, intense desire for something. Oftentimes referred to as a sexual desire (hence the word “erotic” from Greek erotikos).
Plato, however, thinks of eros as a common desire that seeks transcendental beauty. The particular beatuy of an individual is meant to remind us of true beauty that exists in the World of Forms.
“He who loves the beautiful is called a lover because he partakes of it.” (Phaedrus 249E)