1.
a copy of a printed work offered for distribution
2.
the act of issuing printed materials
3.
the communication of something to the public; making information generally known
4.
the business of issuing printed matter for sale or distribution
In 1693, the postage rate of a letter was determined by how much light went through the letter. The less the light went through the letter the more expensive the rate would be. This technique was referred to as candling.