The comparative form of an adjective or adverb WordNet 3.0 & Open English WordNet

In general linguistics, the comparative is a syntactic construction that serves to express a comparison between two entities or groups of entities in quality or degree - see also comparison for an overview of comparison, as well as positive and superlative degrees of comparison. Wikipedia

Syntactic construction that serves to express a comparison between two things or groups of things. Wikipedia Disambiguation

Degree of comparison for adjectives and adverbs Wikidata

A construction showing a relative quality, in English usually formed by adding more or appending -er. For example, the comparative of green is greener; of evil, more evil. Wiktionary

The form of an adverb or adjective modified by more or ending in -er that is used when comparing two things. Wiktionary