διάκονον (diakonos in Strongs or diakonon in the Englishman's Concordance) occurs twice in Romans 15:8 and 16:1.  It refers to attendant, waiter or servant (or technically can reference deacon or deaconess). 

Both actually serve HIM, as we all do.
 
διάκονοι and διακόνους are the represents in discussion of office of Deacon in 1 Timothy 3.

The office of Elder in Titus 1:5 is πρεσβυτέρους (presbuteros (presbyterois) in Strongs), if that is what you are referring to.

Bishop, Deacon and Elder all require the husband of one wife γυναικὸς (gunē) that rules his household well, as Abraham did in Genesis 18.  Phebe did not have a wife.     

Is this sufficient for your request of a study on servant?  There are many other primes and derivatives, did you wish to discuss any of them?