A more thorough explanation:

Definition: Locus sigilli (L.S.) is a Latin term that means "the place of the seal." It is commonly used on notarial certificates to indicate where the notary public's embossed seal should be placed.

For a long time, seals were required to be made of wax and affixed to the parchment or paper on which the terms of the instrument were written. The wax was required to have an identifiable impression made upon it, usually by a signet ring. However, as people who did not have signet rings learned to read and write, substitutes for the traditional seal were accepted by the law. Today, a seal may consist of wax, a gummed wafer, an impression on the paper, the word "seal," the letters "L.S." (locus sigilli), or even a pen scratch.

Example: When a notary public signs a document, they will often include the letters "L.S." at the end of their signature. This indicates where their embossed seal should be placed on the document.

Example: In some legal documents, the word "seal" or the letters "L.S." may be used to indicate that the document is intended to be legally binding.

These examples illustrate how the term "locus sigilli" is used to indicate the place where a seal should be affixed to a document, and how it can be used as a legal indicator of a document's validity.