What is Self-clearance?

Self-clearance definition and meaning on Dictionary terms:
the act of clearing.
the distance between two objects; an amount of clear space: The bridge allowed a clearance of 37 feet at mean high water.
a formal authorization permitting access to classified information, documents, etc.
Also called clearance sale. the disposal of merchandise at reduced prices to make room for new goods: He bought the coat for half price at a clearance.
a clear space; a clearing: The house stood in a clearance among the trees.
Banking. an exchange of checks and other commercial paper drawn on members of a clearinghouse, usually effected at a daily meeting of the members.

Machinery. a space between two moving parts, left to avoid clashing or to permit relatively free motion.
the angle between a face of a cutting tool, as a lathe tool, and the work.
Nautical. the clearing of a ship at a port.Also called clearance papers.the official papers certifying this.

Medicine/Medical. a test of the excretory function of the kidneys based on the volume of blood that is cleared of a specific substance per minute by renal excretion.