appraisal (as a noun) is the act of estimating or developing an
opinion of value.
An appraisal (as an adjective) is relating to appraisal functions such as appraisal practice or appraisal services.
estate appraisals are appraisals of real estate, which is generally a parcel of
land and those things permanetly affixed to the land.
Real property is generally considered the interests, rights and benefits of and in a parcel of land.
appraisals are to estimate market value for lending purposes. Such
appraisals are generally controlled by the requirements of USPAP (Uniform
Standards of Professional Appraisal Practice) and the licensing authority of the
2010 USPAP can be viewed on line here: 2016-17