oil, fat
油 centers on oily substances: liquid oil and solid fat. Both meanings share the idea of a greasy, slippery substance used for cooking, fuel, or lubrication.
油 combines 氵 (water/liquid) with 由, which likely contributes the sound. The character originally referred to a specific river name, but later came to mean oil or fat in general.
The left side 氵 is water, and the right side 由 looks like a bottle or container. Imagine pouring oil from a bottle into water—the oil floats and spreads, showing it's a different kind of liquid.
For ユ, picture you slipping on a patch of oil: you -> ユ, and the oil makes the floor dangerously slick.
oil
soy sauce; soya sauce; shoyu
oil; petroleum
negligence; carelessness; inattention; unpreparedness
refueling (a car, plane, etc.)
crude oil
oil pressure
kerosene; paraffin; lamp oil
sesame oil
fats and oils
oil painting
oil field
essential oil; volatile oil
(Chinese) chili oil; chile oil; chilli oil
abura-age; thin deep-fried slices of tofu
oil painting
salad oil; vegetable oil
oil-based
oil content
diesel oil; diesel fuel; gas oil