In Greek:
Quoteνόμωι (γάρ φησι) γλυκὺ καὶ νόμωι πικρόν, νόμωι θερμόν, νόμωι ψυχρόν, νόμωι χροιή, ἐτεῆι δὲ ἄτομα καὶ κενόν (Tetralogies of Thrasyllus, 9; Sext. Emp. adv. math. VII 135)
νόμωι "by custom, conventionally" is an interesting word to use, and I'm not sure I completely disagree with Democritus. We are all - everything - is literally temporary arrangements of atoms and void. That doesn't mean we're not "real". If one drills down far enough, you end up with atoms and void. But through our arrangements of atoms, we interact with the world, each other. Epicurus himself or Lucretius said atoms don't have color or smell or taste, but arrangements give rise to color and smell and taste.
Edit: I suppose I should also include ἐτεῆι δὲ ἄτομα καὶ κενόν. That word does mean "in reality." LSJ uses Democritus's quote in its definition.
Henry George Liddell, Robert Scott, A Greek-English Lexicon, ἐτεός