What does FL OZ stand for?

Fluid Ounce

A fluid ounce is a unit of volume typically used for measuring liquids. It is equivalent to approximately 30 millilitres. Whilst various definitions have been used throughout history, two remain in common use: the imperial and the United States customary fluid ounce. An imperial fluid ounce is  1⁄20 of an imperial pint,  1⁄160 of an imperial gallon or approximately 28.4 ml. A US fluid ounce is  1⁄16 of a US fluid pint,  1⁄128 of a US liquid gallon or approximately 29.6 ml.