What is the meaning of Bit_bucket?

A container for holding chad (small punched-out pieces of paper) from paper tape or punch cards used with teleprinters, early computers, and other machines; a chad box.

The supposed place where bits (binary digits) go when they fall off the end of a register during a shift operation; the notional resting place of lost or missing digital information.

To delete.

Source: wiktionary.org