Labelled and labeled both are correct spellings of the past tense of the verb “label,” which means “attach a label to something” or “categorize something or someone.” The spelling depends on the type of English you use:
In British English, “labelled” with a double “l” is standard.
In American English, “labeled” with one “l” is correct.
Examples: Labelled or labeled in a sentence
Susie has accidentally labelled/labeled all the jeans incorrectly.
I was labelled/labeled a rebel as a teenager.
Leron labelled/labeled every book on the shelf in one afternoon.
Examples: Labelling or labeling in a sentence
I don’t like labelling/labeling people I barely know.
I was labelling/labeling my clothes when you rang me. Labelling/labeling someone based on one encounter is not fair.