Marline \Mar"line\, n. [LG. marlien, marling, or D. marling, marlijn, fr. D. marren to tie, prob. akin to E. moor, v., and lijn line: cf.F. merlin. See Moor, v., Line.]

(Naut.) A small line composed of two strands a little twisted, used for winding around ropes and cables, to prevent their being weakened by fretting.

Marline spike, Marling spike (Naut.), an iron tool tapering to a point, used to separate the strands of a rope in splicing and in marling. It has an eye in the thick end to which a lanyard is attached. See Fid. [Written also marlin spike]

Marline-spike bird. [The name alludes to the long middle tail feathers.]

(Zo["o]l.)
   (a) A tropic bird.
   (b) A jager, or skua gull.

Source: Webster's Revised Unabridged Dictionary (1913)