decuman

/D EH1 K Y UW0 M AH0 N/
adjective
  1. 1

    (historical) Connected with the principal gate of an Ancient Roman camp, near which the tenth cohort of the legion was stationed.

  2. 2

    (obsolete) Large; chief; applied to an extraordinary billow, supposed by some to be every tenth in sequence.

noun
  1. 1

    (obsolete) An extraordinarily large billow.