trade secret

The composition of this sauce is a trade secret, but a variety of similar sauces are found on the market.

Its composition is a trade secret, but its chief ingredient is rubber.

He merely kept his trade secret, because he had to keep his tricks secret, like any other conjurer.

This was a wonderful discovery, and was preserved as a trade secret for a long time.

But whether I practice Yoga, Dianetics, or write the lines on a sugarcoated pill and swallow it is my trade secret.