Types of olive oil compared
Supermarket shelves list many names for what looks like the same product. The article types of olive oil explained sorts them out in detail.
Extra virgin and virgin
Both are unrefined. Extra virgin meets the strictest standards, while virgin oil allows slightly higher acidity and minor flavor flaws.
Refined and light
These start as lower quality oil that is refined to remove defects, then blended with a little virgin oil. Light refers to flavor and color, not calories.
Pomace
Pomace oil is extracted from the leftover pulp using solvents and heat. It is inexpensive and neutral, suited to high volume frying.