As used in this article, the following words and phrases used herein shall have the following meaning ascribed to them:

(a) BUILDER. Any individual, partnership, firm, or corporation that constructed, or performed or managed the construction of, an improvement, or any portion thereof, on or to real estate, and at the time of the construction was licensed as a general contractor in the State of Alabama.

(b) ARCHITECT. Any individual who, at the time the architectural services were performed, was legally qualified to practice architecture and held an unexpired registration as an architect in the State of Alabama; any partnership, corporation, professional corporation, or professional association which, at the time the architectural services were performed, was legally qualified to practice architecture in the State of Alabama; and all employees or agents of the registered architect or of his or her entity or firm acting under the instruction, control, or supervision of the registered architect.

(c) ENGINEER. Any individual who, at the time the engineering services were performed, was legally qualified to practice engineering and held an unexpired registration as a professional engineer in the State of Alabama; any individual who, at the time the engineering services were performed, was legally qualified to practice engineering and was certified as an engineer-in-training in the State of Alabama; any partnership, firm, or corporation which, at the time the engineering services were performed, was legally qualified to practice engineering and held an unexpired certificate of authorization to practice engineering in the State of Alabama; and all employees or agents of the registered engineer or of his or her entity or firm acting under the instruction, control, or supervision of the registered engineer.

(d) SUBSTANTIAL COMPLETION OF CONSTRUCTION OR CONSTRUCTION OF IMPROVEMENT. The time at which the construction of the improvement on or to real estate is sufficiently completed so that the owner, tenant, or other person can occupy or utilize the improvement, or a designated portion thereof, for the use for which it is intended.

(e) CAUSE OF ACTION ACCRUES OR ARISES. The time when a person is injured, including injury which results in death, or when property is damaged as a proximate result of a defect or deficiency in design, planning, testing, supervision, administration, or observation of construction of an improvement by an architect or engineer or in the construction of an improvement on or to real estate, constructed, performed, or managed by a builder; or where the damage or injury either is latent or by its nature is not discoverable in the exercise of reasonable diligence at the time of its occurrence, the claim for relief shall be deemed to arise or accrue at the time the damage or injury is or in the exercise of reasonable diligence should have been first discovered, whichever is earlier. The cause of action accrues or arises whether or not the full amount of damages is apparent at the time of the first injury or damage, and cannot be extended as a continuous wrong. Property damage shall include both physical damages to, and defective condition of, the property.

(f) CONSTRUCTION or CONSTRUCTED. Includes building, constructing, erecting, fabricating, or assembling.

(g) IMPROVEMENT ON OR TO REAL PROPERTY. Anything that is constructed on or to real property, whether on, under, or over land or water, that enhances the value of real property permanently for general uses, including, without limitation, buildings, structures, fixtures, walls, fences, locks, dams, embankments, bulkheads, docks, jetties, drilling and other platforms and rigs, highways, bridges, canals, ditches, waterways, railroads, sewers, pipelines, pole lines, storage tanks, machinery, equipment and other improvements, and any extension, alteration, addition, or portion thereof.