means A person who arranges or encourages romantic relationships or marriages between others, often professionally.

from A transparent compound of "match" plus "maker." The "match" here is the sense of two people well-suited or paired together — a meaning that grew alongside "match" as an equal or counterpart, from Old English "gemæcca," a mate or companion. So a matchmaker literally makes matches: pairs people the way one might pair gloves. (Note this "match" is unrelated to the fire-starting matchstick, which arrived later from a quite separate root.)