NSF certifies drinking water filters to standards applicable to each type of treatment option. You may notice the NSF mark on a product along with numbers such as NSF/ANSI 53 or NSF/ANSI 42, which refer to the standard to which the filter has been certified.
The definition of a canon is a principle, law or standard by which people are judged or a member of the clergy living according to these principles or laws. An example of a canon is a moral principle that a group believes is correct or proper.
Definition of artery. plural. arteries. 1 : any of the tubular branching muscular- and elastic-walled vessels that carry blood from the heart through the body. 2 : a channel (such as a river or highway) of transportation or communication; especially : the main channel in a branching system.