Is Error Term and SSE the same thing?

CFA Level II Quant
#1

From CFA glossary

Error term: The portion of the dependent variable that is not explained by the independent variable in the regression.

From SchewserNotes

Sum of squared errors: measures the unexplained variation in the dependent variable. It’s also known as the sum of squared residuals or the residual sum of squares.

To me, the definition points to the same thing.

#2

They’re not the same thing, but they’re related.

There’s an error term for each data point.

SSE squares each of those error terms, then sums the squares.