"Digital learning" is the 2010's buzz word for educational technology, i.e. defines learning that uses technology in one way or another. As with any synonym, it may convey a slightly different meaning. Educational technology conveys both the idea of learning through technology (computer-based training, simulations, serious gaming, microworlds, etc.) and learning with technology (e.g. using productivity or cognitive tools). Digital learning also may include digital literacy, i.e. teaching young people how to use technology and develop all sorts of 21th century skills.
Digital Literacy Digital literacies go beyond technical proficiency, extending to the issues, norms, and habits that arise from the purposeful use of technology. Digital literacy focuses on why, when, who, and for whom.
"Digital education" is another variant, and probably has the same connotations as "digital learning". E-learning can be either considered as synonym for digital learning and educational technology, or refer to a more specific form that emphasizes online contents and quizzes.
2 Other definitions
“Digital learning is any type of learning that is accompanied by technology or by instructional practice that makes effective use of technology. It encompasses the application of a wide spectrum of practices including: blended and virtual learning.” (Wikipedia). As of April 25, 2019 it is very interesting to notice that this page has poor contents and that there is no link to the educational technology.article, which is now much better developed than 15 years ago. (Notice: I did add the link after looking at this page.).
Educause provides a definition that seems to be "exotic", i.e. not used by many: “The term digital learning or personalized learning can refer to a broad range of services, tools, and curricular models designed to create individualized learning for students. The concept intersects—and overlaps—with notions including adaptive learning, differentiated instruction, competency-based education, and analytics.”
World-wide, since 2004, digital learning and digital education are on a raise with respect to "educational technology". There also exist regional differences. Digital education also could refer to IT education.