(1):

(v. i.) To unite by apposition or contact, as two tubular vessels at their extremities; to anastomose.

(2):

(v. i.) To intercommunicate; to interjoin.

(3):

(v. t.) To unite by apposition or contact, as two vessels in an animal body.

(4):

(v. t.) To unite intimately; to cause to become as one.