Course of dealing and trade usage are standards used to interpret the meaning of agreements in dispute. A course of dealing is a sequence of previous conduct between the parties to a particular transaction which is fairly to be regarded as establishing a common basis of understanding for interpreting their expressions and other conduct.
A usage of trade is any practice or method of dealing having such regularity of observance in a place, vocation or trade as to justify an expectation that it will be observed with respect to the transaction in question. Such a usage may be proved by being embodied in a written trade code or similar other means.
The following is an example of an excerpt of a state statute involving course of dealing and trade usage:
"(3) A course of dealing between parties and any usage of trade in the
vocation or trade in which they are engaged or of which they are or should
be aware give particular meaning to and supplement or qualify terms of
an agreement.
(4) The express terms of an agreement and an applicable course of dealing
or usage of trade shall be construed wherever reasonable as consistent
with each other; but when such construction is unreasonable, express terms
control both course of dealing and usage of trade and course of dealing
controls usage of trade.
(5) An applicable usage of trade in the place where any part of performance
is to occur shall be used in interpreting the agreement as to that part
of the performance.
(6) Evidence of a relevant usage of trade offered by one party is not
admissible unless and until he has given the other party such notice as
the court finds sufficient to prevent unfair surprise to the latter."
