Definition
Twitter Card
Rich media attachments that enhance tweets with images, videos, or summaries.
Twitter Cards are a way to attach rich photos, videos, and media experiences to tweets that link to your content. By adding a few lines of meta tags to your webpage, users who tweet links to your content will have a "card" added to their tweet. Card types include Summary, Summary with Large Image, App, and Player cards. The most common for websites is Summary Large Image, which displays a large, prominently featured image.