vei

Vei is a noun in Norwegian and Bokmål that means road, way, or route. It appears in everyday phrases and compounds such as motorvei (motorway) or bussvei (bus route). The definite form is veien, and the plural is veier. The word derives from Old Norse vegr, meaning a path or road. In other languages, similar terms exist with different spellings, such as Danish vej for road.

VEI, in uppercase as an acronym, stands for the Volcanic Explosivity Index. It is a logarithmic scale used by volcanologists to classify the explosiveness of volcanic eruptions. The VEI combines erupted tephra volume, plume height, and qualitative observations, and it runs from 0 to 8, with higher numbers indicating more explosive eruptions. Rough ranges for tephra volume commonly cited on the scale include: VEI 1 about 0.001 to 0.01 cubic kilometers, VEI 2 about 0.01 to 0.1 km3, VEI 3 about 0.1 to 1 km3, VEI 4 about 1 to 10 km3, VEI 5 about 10 to 100 km3, VEI 6 about 100 to 1000 km3, VEI 7 about 1000 to 10,000 km3, and VEI 8 greater than 10,000 km3. Plume height is another contributing factor for some ranges. The VEI is widely used to compare eruptions and assess hazards, but it is not predictive of future activity or impacts by itself.

In summary, vei can refer to a common Norwegian word for road or to the scientific VEI scale, depending on context.