What term refers to a memorable phrase often utilized in advertisements?

The term that refers to a memorable phrase often used in advertisements is best identified as a slogan. A slogan is designed to be catchy and succinct, making it easy to remember while conveying the essence of a brand or product. It serves to encapsulate the product's value, appeal to the target audience, and enhance brand recognition.

While "tagline" may sometimes be interchanged with "slogan," it typically refers to a specific phrase associated with a brand throughout its advertising and marketing efforts, often serving a more strategic function that links the core message of the brand. A "catchphrase" is generally a popular saying or expression that may not be tied specifically to advertising and can come from various sources like popular culture or media. "Mantra," on the other hand, tends to denote a guiding principle or motivational phrase rather than being focused on commercial messaging.

In the context of advertisements specifically, the choice of "slogan" accurately reflects the common usage intended in the question, as it is primarily used to create memorable marketing messages.