Pub. 946, How to Depreciate Property (2020), IRS:

The Modified Accelerated Cost Recovery System (MACRS) is used to recover the basis of most business and investment property placed in service after 1986. MACRS consists of two depreciation systems, the General Depreciation System (GDS) and the Alternative Depreciation System (ADS). Generally, these systems provide different methods and recovery periods to use in figuring depreciation deductions.