"pointed iron tool used by sailors to separate strands of rope," 1620s, from spike (n.) + Middle Dutch marlijn "small cord," from marlen "to fasten or secure (a sail)," probably frequentative of Middle Dutch maren "to tie, moor" (see moor (v.)). Influenced in Dutch by Dutch lijn "line" (n.).[marlinspike etymology, marlinspike origin, 英语词源]