CTA stands for "call-to-action" and refers to a prompt or directive given to the user to take a specific action. CTAs are commonly used in marketing and advertising to encourage users to engage with a brand or take a desired action, such as making a purchase, signing up for a newsletter, or filling out a form.

CTAs can take many forms, such as buttons, links, or images, and are typically designed to stand out visually and use persuasive language to encourage the user to take action. CTAs may also be personalized based on the user's behavior or interests, such as showing a different CTA to a first-time visitor versus a repeat customer.

Effective CTAs are often clear, concise, and relevant to the user's context and interests. They should also be strategically placed in a prominent location on the webpage or marketing material, such as above the fold or at the end of an email. By using compelling CTAs, businesses can increase engagement, conversions, and ultimately, revenue.