A banner ad is a type of online advertisement that appears on a website, typically at the top or bottom of a webpage. It consists of a rectangular image or graphic, usually with a short message and a call-to-action (CTA) button.

Banner ads are designed to grab the attention of website visitors and entice them to click on the CTA button, which takes them to the advertiser's website or landing page. They can be static or animated, and may contain text, images, or both.

Banner ads are commonly used for various purposes, such as promoting products or services, building brand awareness, or driving traffic to a specific webpage. They can be targeted to specific audiences based on demographics, interests, or behavior, and can be displayed on websites that are relevant to the advertiser's industry or niche.

Overall, banner ads are an effective way to reach a large audience and increase brand visibility online. However, their effectiveness depends on various factors such as the design, placement, and targeting strategy used.