indenture

v. bind a person in service to another for a specified period of time

n. contract which binds a person to serve another for a specified period of time; written agreement made in duplicate; deed, contract, agreement; indentation

The term indenture comes from the medieval English "indenture of retainer" — a legal  contract written in duplicate on the same sheet, with the copies separated by cutting along a jagged (toothed, hence the term "indenture") line so that the teeth of the two parts could later be refitted to confirm authenticity.
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Noun
1. a concave cut into a surface or edge (as in a coastline)
(synonym) indentation
(hypernym) concave shape, concavity, incurvation, incurvature
(hyponym) notch
2. formal agreement between the issuer of bonds and the bondholders as to terms of the debt
(hypernym) written agreement
3. a contract binding one party into the service of another for a specified term
(hypernym) contract
(derivation) indent
4. the space left between the margin and the start of an indented line
(synonym) indentation, indent
(hypernym) space, blank space, place
Verb
1. bind by or as if by indentures, as of an apprentice or servant; "an indentured servant"
(synonym) indent
(hypernym) oblige, bind, hold, obligate

n. indenture, contract which binds a person to serve another for a specified period of time

(v. t.)
To indent; to make hollows, notches, or wrinkles in; to furrow.
  

(v. t.)
To bind by indentures or written contract; as, to indenture an apprentice.
  

(v. i.)
To run or wind in and out; to be cut or notched; to indent.
  

(n.)
The act of indenting, or state of being indented.
  

(n.)
A mutual agreement in writing between two or more parties, whereof each party has usually a counterpart or duplicate; sometimes in the pl., a short form for indentures of apprenticeship, the contract by which a youth is bound apprentice to a master.