What is the difference between EDP, EDT, perfume, & cologne?

The difference between different types of fragrances is concentration, though in some instances an EDT and EDP will have different formulations as well.

In order from strongest to weakest:

• Perfume – richest and longest-lasting product of a fragrance line with 20-40% aromatic compounds.
• Parfum – contains between 10-30% aromatic compounds, making it the second strongest fragrance.
• Eau de Toilette – a perfume solution with a 3-8% aromatic compound in an oil and water base.
• Eau de Fraiche – the lowest concentration, with 1-3% essential oils.
• Eau de cologne – French for "Water from Cologne", a citrusy, light perfume with a typical concentration of about 2-5% aromatic compounds