di·a·gram 
(dīə-grăm′)
(dīə-grăm′)n.
1. A plan, sketch, drawing, or outline designed to demonstrate or explain how something works or to clarify the relationship between the parts of a whole.
2. Mathematics A graphic representation of an algebraic or geometric relationship.
3. A chart or graph.
tr.v. di·a·grammed, di·a·gram·ming, di·a·grams or di·a·gramed or di·a·gram·ing
To indicate or represent by or as if by a diagram.
[Latin diagramma, figure, from Greek, a figure worked out by lines, plan, from diagraphein, to mark out, delineate : dia-, dia- + graphein, to write; see gerbh- in the Appendix of Indo-European roots.]
dia·gram′ma·ble adj.
di′a·gram·matic (-grə-mătĭk), di′a·gram·mati·cal adj.
di′a·gram·mati·cal·ly adv.