[tran-suh m]
  1. a crosspiece separating a door or the like from a window or fanlight above it.
  2. Also called transom light, transom window. a window above such a crosspiece.
  3. a crossbar of wood or stone, dividing a window horizontally.
  4. a window so divided.
  5. Nautical.
    1. a flat termination to a stern, above the water line.
    2. framework running athwartships in way of the sternpost of a steel or iron vessel, used as a support for the frames of the counter.
  6. Artillery. a metal piece connecting the sidepieces of the tail or the cheeks of a gun carriage.

Origin of transom

1325–75; late Middle English traunsum, traunsom, Middle English transyn, probably alteration (by association with trans-) of traversayn < Old French traversin crosspiece, derivative of travers breadth; see traverse
Related formstran·somed, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for transom

Contemporary Examples of transom

Historical Examples of transom

  • Now roost on the transom, over there in the corner, Stryker, and don't move.

    The Black Bag

    Louis Joseph Vance

  • If the stern was square, the transom was set at a rake of not less than 45.

  • The arch of the transom must be marked, and the hull cut down to the sheer.

    Boys' Book of Model Boats

    Raymond Francis Yates

  • The "hatch" was the transom over the door between the offices.

    The Portygee

    Joseph Crosby Lincoln

  • Cadogan wondered what the man on the transom was thinking of.

    Sonnie-Boy's People

    James B. Connolly

British Dictionary definitions for transom


  1. Also called: traverse a horizontal member across a windowCompare mullion
  2. a horizontal member that separates a door from a window over it
  3. the usual US name for fanlight
  4. nautical
    1. a surface forming the stern of a vessel, either vertical or canted either forwards (reverse transom) or aft at the upper side
    2. any of several transverse beams used for strengthening the stern of a vessel
Derived Formstransomed, adjective

Word Origin for transom

C14: earlier traversayn, from Old French traversin, from traverse
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 transom

mid-14c., transeyn "crossbeam spanning an opening, lintel," probably by dissimilation from Latin transtrum "crossbeam" (especially one spanning an opening), from trans- "across" (see trans-) + instrumental suffix -trum. Meaning "small window over a door or other window" is first recorded 1844.

Online Etymology Dictionary, © 2010 Douglas Harper