one-year rule

Definition from Nolo’s Plain-English Law Dictionary

A rule that requires a patent application to be filed within one year of: 1) any public use of the invention by the inventor, 2) a sale of the invention, 3) an offer to sell the invention, or 4) any description of the invention by the inventor in a published document. Failure to file a patent application within this one-year period results in the invention's passing into the public domain, where it is no longer eligible for a patent. The application of the one-year rule to sales is sometimes referred to as the on-sale bar.

Definition provided by Nolo’s Plain-English Law Dictionary.