marker (n.)

"to put a mark on," Old English mearcian (West Saxon), merciga (Anglian) "to trace out boundaries;" in late Old English "make a mark or marks on," from Proto-Germanic *markojan (source also of Old Norse merkja, Old Saxon markon "appoint, observe, remark," Old Frisian merkia, Old High German marchon "to limit, plan out," German merken "to mark, note," Middle Dutch and Dutch merken "to set a mark on"), from the root of mark (n.1).

Influenced by the Scandinavian cognates. Meaning "to have a mark" is from c. 1400; that of "to notice, observe" is late 14c. Figurative sense of "designate as if by placing a mark on," hence "to destine," is from late Old English. Meaning "be a noteworthy feature of" is by 1660s. To mark time (1833) is from military drill, originally "move the feet as if marching but remain in place."

The verbs in Romanic are from the nouns, which are early borrowings from Germanic: Old French merchier "to mark, note, stamp, brand," French marquer "to mark," Spanish marcar, Italian marcare.