At someone’s service

an act of helpful activity; help; aid:
to do someone a service.
the supplying or supplier of utilities or commodities, as water, electricity, or gas, required or demanded by the public.
the providing or a provider of accommodation and activities required by the public, as maintenance, repair, etc.:
The manufacturer guarantees service and parts.
the organized system of apparatus, appliances, employees, etc., for supplying some accommodation required by the public:
a television repair service.
the supplying or a supplier of public communication and transportation:
telephone service; bus service.
the performance of duties or the duties performed as or by a waiter or servant; occupation or employment as a waiter or servant.
employment in any duties or work for a person, organization, government, etc.
a department of public employment, an administrative division of a government, or the body of public servants in it:
the diplomatic service.
the duty or work of public servants.
the serving of a sovereign, state, or government in some official capacity.
Military.

the armed forces:
in the service.
a branch of the armed forces, as the army or navy:
Which service were you in during the war?

Ordnance. the actions required in loading and firing a cannon:
service of the piece.
Often, services. the performance of any duties or work for another; helpful or professional activity:
medical services.
something made or done by a commercial organization for the public benefit and without regard to direct profit:
Certain books are published at a loss as a public service.
Also called divine service. public religious worship according to prescribed form and order.
a ritual or form prescribed for public worship or for some particular occasion:
the marriage service.
the serving of God by obedience, piety, etc.:
voluntary service.
a musical setting of the sung portions of a liturgy.
a set of dishes, utensils, etc., for general table use or for particular use:
a tea service; service for eight.
.
Law. the serving of a process or writ upon a person.
Nautical. tarred spun yarn or other small stuff for covering the exterior of a rope.

the act or manner of putting the ball or shuttlecock into play; .
the ball or shuttlecock as put into play.

the mating of a female animal with the male.
of service; useful.
of, relating to, or used by , delivery people, etc., or in food:
service stairs; the service pieces in a set of dishes.
supplying aids or services rather than products or goods:
Medicine is one of the service professions.
supplying maintenance and repair:
He operates a service center for electrical appliances.
of, for, or pertaining to the armed forces of a country or one of them:
a service academy.
charged for providing service:
a service fee of 15 percent on the restaurant check.
providing, authorizing, or guaranteeing service:
a service industry; a service contract.
to make fit for use; repair; restore to condition for service:
to service an automobile.
to supply with aid, information, or other incidental services.
(of a male animal) to mate with (a female animal).
Finance. to pay off (a debt) over a period of time, as by meeting periodic interest payments.
at someone’s service, ready to be of help or use to someone; at one’s disposal:
You will have an English-speaking guide at your service.
be of service, to be helpful or useful:
If we can be of service, do not hesitate to call.
noun
an act of help or assistance
an organized system of labour and material aids used to supply the needs of the public: telephone service, bus service
the supply, installation, or maintenance of goods carried out by a dealer
the state of availability for use by the public (esp in the phrases into or out of service)
a periodic overhaul made on a car, machine, etc
the act or manner of serving guests, customers, etc, in a shop, hotel, restaurant, etc
a department of public employment and its employees: civil service
employment in or performance of work for another: he has been in the service of our firm for ten years
the work of a public servant

one of the branches of the armed forces
(as modifier): service life

the state, position, or duties of a domestic servant (esp in the phrase in service)
the act or manner of serving food
a complete set of dishes, cups, etc, for use at table
public worship carried out according to certain prescribed forms: divine service
the prescribed form according to which a specific kind of religious ceremony is to be carried out: the burial service
a unified collection of musical settings of the canticles and other liturgical items prescribed by the Book of Common Prayer as used in the Church of England
(sport)

the act, manner, or right of serving a ball
the game in which a particular player serves: he has lost his service Often shortened to serve

(in feudal law) the duty owed by a tenant to his lord
the serving of a writ, summons, etc, upon a person
(nautical) a length of tarred marline or small stuff used in serving
(of male animals) the act of mating
(modifier) of, relating to, or for the use of servants or employees
(modifier) serving the public rather than producing goods
verb (transitive)
to provide service or services
to make fit for use
to supply with assistance
to overhaul (a car, machine, etc)
(of a male animal) to mate with (a female)
(Brit) to meet interest and capital payments on (debt)
noun
See service tree
noun
Robert (William). 1874–1958, Canadian poet, born in England; noted for his ballad-like poems of gold-rush era Yukon, such as ‘The Shooting of Dan McGrew’; his books include Songs of a Sourdough (1907)
n.

c.1100, “celebration of public worship,” from Old French servise “act of homage; servitude; service at table; Mass, church ceremony,” from Latin servitium “slavery, condition of a slave, servitude,” also “slaves collectively,” from servus “slave” (see serve (v.)).

Meaning “act of serving, occupation of an attendant servant” is attested from c.1200, as is that of “assistance, help; a helpful act.” From c.1300 as “provision of food; sequence of dishes served in a meal;” from late 14c. as “service at table, attendance during a meal.” Meaning “the furniture of the table” (tea service, etc.) is from mid-15c.

Meanings “state of being bound to undertake tasks for someone or at someone’s direction; labor performed or undertaken for another” are mid-13c. Sense of “service or employment in a court or administration” is from c.1300, as is that of “military service (especially by a knight); employment as a soldier;” hence “the military as an occupation” (1706).

Also in Middle English “sexual intercourse, conjugal relations” (mid-15c.; service of Venus, or flesh’s service). Service industry (as distinct from production) attested from 1938. A service station originally was a gas stop that also repaired cars.

type of tree or berry, extended form of serve (perhaps via Middle English plural serves being taken as a singular), from Old English syrfe, Old French sorbe, both from Vulgar Latin *sorbea, from Latin sorbus (see sorb).
v.

1893, “to provide with service,” from service (n.1). Meaning “perform work on” first recorded 1926. Related: Serviced; servicing.
Ready to help someone, at someone’s disposal, as in The tour guide said he was at our service for the rest of the afternoon. [ Second half of 1600s ]
see:

at someone’s service
break someone’s serve (service)
lip service
of service to someone
press into service