According to The Dictionary of Real Estate Appraisal, Third Edition, 1993 

The definition of an appraisal is:

1. An analysis, opinion, or conclusion relating to the nature, quality, value, or utility of specified interests in, or aspects of , identified real estate. (Code of Professional Ethics of the Appraisal Institute) In this usage, appraisal covers a variety of assignments, including valuation, consulting, and review.

2. The act or process of estimating value; an estimate of value. (USPAP, 1992 edition).

The definition of an appraisal process is:

A systematic procedure employed to provide the answer to a client's question about the value of real property.