Can we use superlative when we are talking about 2 or more items? I’m not quite sure about that since the rule says: “Superlative adjectives are used to describe an object which is at the upper or lower limit of a quality”.
I wanted to figure out this before talking to my student who wrote the following sentence:”Only a few games are the most popular in the world”.
Your question is based unfortunately on a badly-worded law; I would opt for Merriam-Webster‘s definition:
The form of an adjective or adverb that is used to indicate the greatest degree of a particular quality
The following examples (from this thread) are all cases in which plural objects are used with superlatives:
Basketball players are among the tallest men in the world.
She is one of the richest women in the world