[1] : The Collaborative International Dictionary of English v.0.48

keelson \keel"son\, n. akin to sw. k"olsvin, dan.
   kj"olsviin, g. kielschwein; apparently compounded of the
   words keel and swine; but cf. norweg. kj"olsvill, where
   svill is akin to e. sill, n.  shipbuilding
   a piece of timber in a ship laid on the middle of the floor
   timbers over the keel, and binding the floor timbers to the
   keel; in iron vessels, a structure of plates, situated like
   the keelson of a timber ship.
   1913 webster

   cross keelson, a similar structure lying athwart the main
      keelson, to support the engines and boilers.
      1913 webster
see also:
cross keelson 

[2] : WordNet (r) 2.0

keelson
     n : a longitudinal beam connected to the keel of ship to
         strengthen it

Keelson >> K Words
Keelson, definition of term: Keelson
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