What is the difference between dementia and Alzheimer’s disease?
Dementia is an umbrella term used to describe a group of diseases characterized by progressive worsening of cognitive function (memory, language, problem-solving and other thinking abilities) that is severe enough to interfere with daily life.
There are various types of dementia, and the most common type is Alzheimer’s disease. About 60-70% of people with dementia do have Alzheimer’s disease.
It is like a rose is one specific kind of flower, whereas the word "flower" is used to refer to anything that is "the part of a plant that produces new seeds".