See also: PAROL EVIDENCE–Interpretation of Terms
WORDS AND PHRASES–Other Evidence.
Evidence of industry-wide usage will be admitted to establish the meaning of terms of art or even to establish undefined terms in some cases.  Note that the best evidence rule will preclude admission of such secondary evidence where it is being offered in place of an existing contract.{footnote}Amoco Production v. United States, 455 F. Supp. 46 (D. Utah 1977).{/footnote}