What is Concurrence?

Legal Definition
In Western jurisprudence, concurrence (also contemporaneity or simultaneity) is the apparent need to prove the simultaneous occurrence of both actus reus ("guilty action") and mens rea ("guilty mind"), to constitute a crime; except in crimes of strict liability. In theory, if the actus reus does not hold concurrence in point of time with the mens rea then no crime has been committed.
-- Wikipedia
Legal Definition
French law. The equality of rights, or privilege which several persons-have over the same thing; as, for example, the right which two judgment creditors, Whose judgments were rendered at the same time, have to be paid out of the proceeds of real estate bound by them. Dict. de Jur. h. t.
-- Bouviers Law Dictionary
Legal Definition
In French law. The possession, by two or more persons, of equal rights or privileges over the same subject-matter. See Concurrence deloyale.
-- Black's Law Dictionary