Nor Easter
In short
A large-scale extratropical cyclone that occurs along the northern Atlantic coast of North America. These storms are named after the northeasterly winds they produce.
In plain words
These are powerful storms that bring heavy rain, snow, or blizzards to the coast. They usually start near the shore between North Carolina and Massachusetts. They can cause big waves and flooding.
A simple example
A winter storm hits the coast of New England, bringing freezing winds from the northeast and burying cities in several feet of snow.
Why it matters
They can cause serious damage through coastal erosion and hurricane-force winds. The heavy snow and flooding often disrupt transport and power for many people.
Easy to mix up
Do not confuse them with hurricanes, which form in different tropical conditions and have different wind patterns.