Diagram
early 17th century: from Latin diagramma, from Greek, from diagraphein ‘mark out by lines’, from dia ‘through’ + graphein ‘write’.
wiktionary
From French diagramme, from Italian diagramma, from Ancient Greek διάγραμμα(diágramma)
etymonline
diagram (n.)
1610s, "an illustrative figure giving only the outlines or general scheme of the object;" 1640s in geometry, "a drawing for the purpose of demonstrating the properties of a figure;" from French diagramme, from Latin diagramma "a scale, a musical scale," from Greek diagramma "geometric figure, that which is marked out by lines," from diagraphein "mark out by lines, delineate," from dia "across, through" (see dia-) + graphein "write, mark, draw" (see -graphy). Related: Diagrammatic; diagrammatically.
The verb, "to draw or put in the form of a diagram," is by 1822, from the noun. Related: Diagrammed; diagramming.
