Adaptive design and responsive design may sound similar but they are a bit different. There maybe some overlap. Adaptive design should be incorporated in responsive design.
Adaptive design focuses on displaying or rendering information that is appropriate for the device on which it is being viewed and may consider the performance of its network connection.
For example, when a user is viewing a website on a laptop or desktop computer that has a good Wi-fi or hardwire connection, displaying high resolution images, videos and other rich content is not a problem. High resolution images, video and other rich content could impact your site visitors experience on a mobile device. It could slow down your website response time to render it or it may not be appropriate to attempt to display the screen of a mobile phone. This can cause users to bounce.
When thinking about your website content for mobile users, think response time and what is appropriate. For example, switching to lower resolution images will reduce their file size and speed up rendering on a mobile phone. Maybe there is content that doesn’t present well on a mobile device. In those cases, it maybe more appropriate to not render or hide that information from rendering on a mobile device.
Don’t cause your website visitors to bounce because it is not adapting its content rendering for the device on which it is being view.
Here are a couple of links about Adaptive Design.
GiantFocal – The Beginner’s Guide to Adaptive Web Design
webopedia – Adaptive Web Design