What term describes a word that has taken on a more positive connotative meaning than its denotative meaning?

The term that describes a word taking on a more positive connotative meaning than its denotative meaning is indeed elevation. This concept involves the transformation of a word's meaning over time, where it develops more favorable associations. For instance, the word "knight" in medieval times referred to a servant or attendant, but it has since evolved to connote nobility and valor.

In this context, elevation specifically emphasizes the positive shift in meaning, distinguishing it from other transformations of word meanings. The other options may relate to language change but do not reflect the specific idea of a word gaining positive connotations. Deterioration refers to a negative change in meaning, neologism pertains to the creation of new words, and semantic shift encompasses a broader range of meaning changes, including both positive and negative shifts.