The difference between a hot tub and a whirlpool is the whirlpool is the action that occurs when the hot tub is operating.
And a Hot Tub is a large tub or small pool full of water used for hydrotherapy, relaxation or pleasure.
Some hot tubs also have powerful jets for massage purposes.
Whirlpool is the term used to refer to any hot tub or spas circular "water action".
Some Hot Tubs or Jacuzzi's are also called Whirlpools and named Whirlpool Jacuzzi's.
Also the word “hot tub” is often used synonymously with the word “Jacuzzi,” but in reality there are a few subtle but important differences between the two.
Hot tubs are large tubs of hot water that can be used to relax and entertain.
Jacuzzi is a trademarked brand of hot tubs and other products.