Bearer Securities

What does Bearer Securities mean in American Law?

The definition of Bearer Securities in the law of the United States, as defined by the lexicographer Arthur Leff in his legal dictionary is:

Securities, e.g., bonds, are bearer securities, i.e., payable to whomever is in possession, if they (a) are in bearer form (See U.C.C. § 8-102) or (b) carry a blank endorsement.