Terms used in this chapter shall be construed as follows:
(a) “Designers” means any person, firm, or corporation duly authorized pursuant to the laws of this state to engage in the practice of architecture and/or engineering within this state.
(b) “Public works contract” means a contract to perform design or planning services by a designer with the state, any agency, or governmental subdivisions thereof.
(c) “Retained earnings” means any money or earned estimates withheld from a designer pursuant to the terms of a public works contract.