 Alfarabi’s fifth section is related to Aristotle’s De interpretatione. He distinguishes between simple and composite expressions; the simple expresssions are three: name, vocable (kalimah) and instrument. “The vocable, the Arab grammarians know it as the verb (fiʻl), and the instrument they call it the particle (ḥarf)” (Dunlop 1955, 278). Avempace immediately links the classification of terms with the construction of science and he justifies the section saying: