The difference between Extreme and Severe

When used as adjectives, extreme means of a place, the most remote, farthest or outermost, whereas severe means very bad or intense.

Extreme is also noun with the meaning: the greatest or utmost point, degree or condition.

Extreme is also adverb with the meaning: extremely.

check bellow for the other definitions of Extreme and Severe

Extreme as an adjective:

Of a place, the most remote, farthest or outermost.

Examples:

"At the extreme edges, the coating is very thin."
Extreme as an adjective:

In the greatest or highest degree; intense.

Examples:

"He has an extreme aversion to needles, and avoids visiting the doctor."
Extreme as an adjective:

Excessive, or far beyond the norm.

Examples:

"His extreme love of model trains showed in the rails that criscrossed his entire home."
Extreme as an adjective:

Drastic, or of great severity.

Examples:

"I think the new laws are extreme, but many believe them necessary for national security."
Extreme as an adjective:

Of sports, difficult or dangerous; performed in a hazardous environment.

Examples:

"Television has begun to reflect the growing popularity of extreme sports such as bungee jumping and skateboarding."
Extreme as an adjective (archaic):

Ultimate, final or last.

Examples:

"the extreme hour of life"

Extreme as a noun:

The greatest or utmost point, degree or condition.
Extreme as a noun:

Each of the things at opposite ends of a range or scale.

Examples:

"'extremes of temperature"
Extreme as a noun:

A drastic expedient.
Extreme as a noun (mathematics):

Either of the two numbers at the ends of a proportion, as 1 and 6 in 1:2=3:6.

Severe as an adjective:

Very bad or intense.
Severe as an adjective:

Strict or harsh.

Examples:

"a severe taskmaster"
Severe as an adjective:

Sober, plain in appearance, austere.

Examples:

"a severe old maiden aunt"