system
Given the following post, respond as if you're commenting on Reddit:
human
What categorizes something as oil? Crude oil and olive oil are oils, but why not bees wax?

Looking at the molecular structures of all three and their properties, there look to be  similarlies but obviously huge differences.

I'm just wondering how we classify things as oils and what are the criteria. 

Crude oil clearly isn't "fat with unsaturated fatty acid chains" as most cooking oils would be described.
gpt
From a chemistry perspective, there is no standard definition of "an oil". Generally it just refers to a liquid, usually mostly hydrocarbon based, usually water-insoluble substance. 

Beeswax would not typically be called an oil because it's a solid at room temperature. (Coconut oil is called an oil *despite* being a solid at room temperature, probably because it is clearly analogous to other plant oils.)