UMSA
Unincorporated Municipal Services Area. Locations within the county that are currently not part of an established municipality.
Mitigation annual payment made to the county to offset the taxes lost due to incorporating
Ad Valorum tax
a tax levied as a percentage of the value of the item, rather than at a flat rate.  E.g. a tax based upon the assessed value of property. The term "property tax" may be used interchangeably with the term "ad valorem tax."
Millage Rate Is the tax rate set by the taxing authorities. The rate is expressed in mills and is multiplied by your assessed value to determine your tax.
Property Value or Market Value The property appraiser’s best estimate as to how much your house would sell for on the open market.
Assessed Value Portion of your property’s market value which is subject to taxation. It is always less than the market value.
PAC Political Action Committee.
Homestead Exemption Property tax deduction on property value if you own and live in the home. Typical deduction is $25,000 after the first year of residency.

Miami-Dade County Glossary of Terms ...