OG = Original Gravity. We measure this in degrees Plato. The Plato scale expresses the amount of fermentables in a solution as a percentage of extract by weight. This is also a gauge of beer strength. For example, beers in Europe are labeled as 12ºP instead of ~5.0% ABV.
ABV = Alcohol by Volume. This is measured as the amount of ethanol in the beer as a percentage of total volume. Most of our beers are around 5% ABV.
IBU = International Bittering Units. This refers to the amount of isomerized hop resins in the beer. Essentially, it is the perceived bitterness you will experience. The higher the number, the more bitter the beer will be.