A more thorough explanation:

Definition: An invention that an inventor has either deliberately stopped trying to exploit, or else acted in a way that precludes claiming the invention in a later patent.

Abandoned invention is a term used in patent law to describe an invention that an inventor has given up on or abandoned. This can happen if the inventor decides that the invention is not worth pursuing, or if they fail to take the necessary steps to protect their invention. If an inventor abandons their invention, they cannot later claim it in a patent application.

For example, if an inventor creates a new type of machine but decides not to pursue it further, they have abandoned the invention. They cannot later try to patent the machine or claim ownership of it.

Abandoned inventions are not considered prior art to later inventors unless they are publicly known. This means that if another inventor comes up with the same idea later, they can still patent it as long as the abandoned invention was not publicly known.

Abandonment of an imperfect form of an invention does not bar a patent on a later-perfected form. This means that if an inventor abandons an early version of their invention but later improves upon it, they can still patent the improved version.