The basic idea
Eau de Toilette, Eau de Parfum and Parfum generally refer to different fragrance concentration styles, but there is no single universal formula that every brand follows.
EDT
EDT versions are often positioned as lighter or fresher interpretations, although some can still perform strongly.
EDP
EDP versions are commonly richer or more concentrated than a related EDT, but the scent itself may also be reformulated rather than simply strengthened.
Parfum
Parfum or extrait-style releases are often positioned as richer and denser, but the exact effect depends on the formula.
Why the name is not enough
Two fragrances with the same concentration label can behave very differently. Ingredients, structure, skin and climate all affect perception.
How to shop
Compare the exact version, not just the fragrance name. An EDT and EDP of the same line may smell noticeably different.
Shopping note: When a guide links to Amazon, confirm the exact fragrance name, concentration, bottle size and seller before purchasing.