relay

Etymology 1

From Middle French relai (“reserve pack of hounds”), from relaier (“to exchange tired animals for fresh”); literally, "to leave behind", from Old French relaier (“to leave behind”), from re- + laier (“to leave”), of uncertain origin.

noun

1. (hunting, rare) A new set of hounds.
2. (now chiefly historical) A new set of horses kept along a specific route so that they can replace animals that are tired.
3. (by extension) A new set of anything.
4. A series of vehicles travelling in sequence.
5. (athletics) A track and field discipline where runners take turns in carrying a baton from start to finish. The most common events are 4×100 meter and 4×400 meter competitions.
6. (electronics) An electrical actuator that allows a relatively small electrical voltage or current to control a larger voltage or current.

verb

1. (transitive) To pass on or transfer (information).
   The CCTV cameras relay what's going on to the headquarters.
   Can you relay this message to John?
2. (obsolete, intransitive, hunting) To release a new set of hounds.
3. (transitive, now rare) To place (people or horses) in relays, such that one can take over from another.
4. (intransitive, now rare) To take on a new relay of horses; to change horses.

Etymology 2

re- + lay

verb

1. Alternative spelling of re-lay
   Over this section the 16th class are allowed to haul 800 tons, compared with 600 tons only by the 13th and 14th, and 450 tons by the 12th class engines, and in this way, without any expenditure on civil engineering works or relaying with heavier rails, the introduction of the 16th class has almost doubled the line capacity. 1940 December, O. S. M. Raw, “The Rhodesia Railways—II”, in Railway Magazine, page 640
   A reader writes that some Ballachulish branch services are still worked by Class 2 2-6-0s Nos. 46460 and 78052, which have had to be retained at Oban until a tight curve on the outside line of the railway pier, used by coal and oil traffic for the island steamers, has been relaid to standards suitable for the diesels. 1962 December, “Motive Power Miscellany: Scottish Region”, in Modern Railways, page 427