Utility is a term used in economics to represent the level of satisfaction derived from the consumption of a good. It can be thought of as a measure of satisfaction. It may or may not be quantifiable, depending on the type of utility.
Ordinal utility refers to the relative ranking of goods based on the utility they provide. It is not a quantitative method of measuring utility, rather it relies on the consumer’s ability to rank various goods based on the satisfaction derived from them.
This type of utility can be quantified and is more than just a measure of relative ranking. The unit used to measure the amount of utility is called a ‘util’.