A more thorough explanation:

Incorporate by reference means to include language from one document into another document. This is often done to make a secondary document a part of a primary document. It is commonly used to refer to another text, and the receiving text would treat the incorporated text as though it were entirely integrated.

Contract Law: In contract law, if a document is incorporated by reference, it must be described in the contract clearly beyond doubt. For example, a contract may refer to a separate document that outlines the terms and conditions of the agreement.

Patent Law: In patent law, one patent application may include information from another patent application. This is done by explicitly including the information in the new application.

Pleading: In the context of pleading, incorporating by reference is when a litigant integrates part of a prior court brief into an updated brief. For example, a plaintiff may incorporate allegations contained in their original complaint into their amended complaint.

Securities Filings: In securities filings, incorporating by reference is used to make sure that a company met its prospectus delivery requirement before its public offering of securities. A registrant may integrate information from a prior filing into their current filing. For example, a company issuing securities through a Form S-3 may incorporate information from their periodic reports.

These examples illustrate how incorporating by reference is used in different areas of law to make sure that important information is included in a document. By incorporating information from another document, the receiving document can treat the incorporated information as though it were part of the original document.