Complex sentence: In grammar, the superlative of an adjective or adverb is the greatest form of adjective or adverb which indicates that something has some feature to a greater degree than anything it is being compared to in a given context.
Split into simpler sentences: In grammar, the superlative of an adjective or adverb is in the greatest form of the adjective or adverb. This indicates that something has at least one feature to a greater degree than anything it is being compared to in a given context.