Industrial microbes usually make a single substance, such as triglycerides, much like vegetable oil.

Exposure to a few contaminates can often multiply or exacerbate the effects of a single substance.

Instead, a single substance seemed to form the walls and interior.

"Compound", on the other hand, is a relatively specific term, the scientific term meaning "a single substance".

In other words, nylon 6 is made from a single six-carbon substance called caprolactam.

The cooking oil is usually a single substance, the soda pop has many ingredients.

If a single substance fills the universe, is the universe, then its properties limit all that we can do.

"It is the single most toxic substance known to man."

Unlike most blood tests, which measure levels of single substances, the new test looks for patterns of proteins that set cancer patients apart.

In the last quarter century, no single substance has been the subject of more conflicting reports than caffeine.