DAE is the acronym for Digital Asset Exchange.
A Digital Asset Exchange is any trading platform that specializes in, or exclusively deals with, cryptocurrency & digital assets.
Digital Asset Exchanges come in 2 general classifications, centralized and Decentralized. Centralized exchanges are typically compliant with regulation. Moreover, centralized exchanges custody the assets and control their private keys. On the other hand, because decentralized exchanges have no central point of governance, they fall outside of regulatory oversight and typically allow traders to maintain ownership over their assets while using the platform.