Meaning of DOUBLING in English
/dub"ling/ , n. Naut.
the part of the upper or lower end of one spar of a mast that is overlapped by another spar above or below it.
[ 1350-1400; ME; see DOUBLE, -ING 1 ]
Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012