Definition - The degree of an adjective or adverb where it expresses a simple quality without any qualification or comparison.

1. As opposed, for example, to the comparative and superlative degrees which are used to perform comparisons.

Example -

Bill is tall. (positive degree)

Bob is taller than Bill. (comparative)

But Dave is the tallest of the three. (superlative)

Oxford English Dictionary -
The term's first citation in its grammatical sense is from circa 1447:
"Be twyx them tweyn owyth no more to be Than is be twyn a posatyve and a comparatyve degre."
(O. Bokenham Seyntys (Roxb.) 161)

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