No. A fluid ounce is a measure of volume, related to liquids and fluids. An ounce is a unit of weight or mass. A glass of water can have both - the glass and water together have a particular weight...
they are almost the same, one US fluid oz is 29.574 ml and English or Imperial oz as they call it, is about 28.4 ml. Thus, one English fluid oz is 0.96 US fluid oz.