Definitions of indenture:

• noun:   a contract binding one party into the service of another for a specified term
• noun:   formal agreement between the issuer of bonds and the bondholders as to terms of the debt
• noun:   a concave cut into a surface or edge (as in a coastline)
• noun:   the space left between the margin and the start of an indented line
• verb:   bind by or as if by indentures, as of an apprentice or servant

  Example: "An indentured servant"