(1):

(n.) Agreement or consent, implying aid or contribution of power or influence; cooperation.

(2):

(n.) The act of concurring; a meeting or coming together; union; conjunction; combination.

(3):

(n.) A meeting of minds; agreement in opinion; union in design or act; - implying joint approbation.

(4):

(n.) A common right; coincidence of equal powers; as, a concurrence of jurisdiction in two different courts.