a figure, usually consisting of a line drawing, made to accompany and illustrate a geometrical theorem, mathematical demonstration, etc.
a drawing or plan that outlines and explains the parts, operation, etc., of something: a diagram of an engine.
a chart, plan, or scheme.

verb (used with object), di·a·gramed or di·a·grammed, di·a·gram·ing or di·a·gram·ming.

to represent by a diagram; make a diagram of.

Origin of diagram

1610–20; < Latin diagramma < Greek: that which is marked out by lines. See dia-, -gram1
Related formsdi·a·gram·ma·ble, adjectivemis·di·a·grammed, adjectiveun·di·a·gramed, adjectiveun·di·a·grammed, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for diagram

Contemporary Examples of diagram

Historical Examples of diagram

  • Draw a diagram representing the circumference line and pitch in feet.

    Flying Machines

    W.J. Jackman and Thos. H. Russell

  • Mark, however, said he would teach him the lay of the case that evening from a diagram.

    Cleo The Magnificent

    Louis Zangwill

  • And this is most clearly shown when he is taken to a diagram or to anything of that sort.



  • Making the pelvis loop may be easily followed in diagram in Fig. 17.


    Leon Luther Pray

  • The reason for this is best described with the aid of a diagram.

    Submarine Warfare of To-day

    Charles W. Domville-Fife

British Dictionary definitions for diagram



a sketch, outline, or plan demonstrating the form or workings of something
maths a pictorial representation of a quantity or of a relationshipa Venn diagram

verb -grams, -gramming or -grammed or US -grams, -graming or -gramed

to show in or as if in a diagram
Derived Formsdiagrammatic (ˌdaɪəɡrəˈmætɪk), adjectivediagrammatically, adverb

Word Origin for diagram

C17: from Latin diagramma, from Greek, from diagraphein, from graphein to write
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for diagram

1610s, from French diagramme, from Latin diagramma, from Greek diagramma "geometric figure, that which is marked out by lines," from diagraphein "mark out by lines, delineate," from dia- "across, out" (see dia-) + graphein "write, mark, draw" (see -graphy). The verb is 1840, from the noun.

Online Etymology Dictionary, © 2010 Douglas Harper