A breathalyzer or breathalyser (U.K.) (a portmanteau of breath and analyzer/analyser) is a device for estimating blood alcohol content

Blood alcohol content

Blood alcohol content , also called blood alcohol concentration, blood ethanol concentration, or blood alcohol level is most commonly used as a metric of alcohol intoxication for legal or medical purposes....

 (BAC) from a breath sample. Breathalyzer is the brand name of a series of models made by one manufacturer of these instruments (originally Smith and Wesson, later sold to National Draeger), but has become a genericized trademark

Genericized trademark

A genericized trademark is a trademark or brand name that has become the colloquial or generic description for, or synonymous with, a general class of product or service, rather than as an indicator of source or affiliation as intended by the trademark's holder...

 for all such instruments. In Canada, a preliminary non-evidentiary screening device can be approved by Parliament as an approved screening device

Approved screening device

An approved screening device is a device used to measure the blood alcohol level of a suspected drunk driver. It is defined in the Criminal Code of Canada as: approved screening device means a device of a kind that is designed to ascertain the presence of alcohol in the blood of a person and that...

, and an evidentiary breath instrument can be similarly designated as an approved instrument

Approved instrument

The expression approved instrument is a Canadian term defined in the Criminal Code of Canada as: approved instrument means an instrument of a kind that is designed to receive and make an analysis of a sample of the breath of a person in order to measure the concentration of alcohol in the blood of...

.