Welcome to the DHanswers forum! This is a great question, and not all all too basic! I'm sure you'll get many responses, because the definition of the "digital humanities" is something that an international and very diverse community of scholars and practioners is continually formulating -- rethinking, questioning, and demonstrating through projects and collaborations of different sorts.
Our definitions are often therefore a little muddy. (Melissa Terras, in a great keynote presentation at last summer's annual Digital Humanities conference, called the entire community to task for hemming and hawing: "It's... kinda the intersection of...") We need to get better at this! So I'm looking forward to the answers you get.
In the meantime, I'll point you to a few existing attempts and conversations.
The new CUNY Digital Humanities Initiative has put out a fantastic beginner's Resource Guide to the Digital Humanities, which includes a set of links on definitions, but -- even better -- some great pages on sample projects, basic readings, and "hot topics" in DH, which will give you a terrific overview of the scene.
Patrick Svensson has a solid piece (one in a series) in Digital Humanities Quarterly called "The Landscape of Digital Humanities."
A recent post by a UVa graduate student, Chris Forster, on the HASTAC Scholar blogs, attempted to define DH. I recommend it highly, both for Chris's smart formulation of four areas of activity (the use of computational methods for research that couldn't be done any other way; "new media" media studies; the ways technology reshapes the humanities classroom; and the ways it reshapes scholarly communication and the roles in the academy) and for the spirited discussion that followed.
Finally, there's a great project out of the University of Alberta, called the "Day in the Life of the Digital Humanities." For the past two years, they've hosted an event in which, for one day, digital humanists from all areas of the field (scholars, administrators, developers, librarians, archivists, students, researchers) blog about and reflect on what they do. The sign-up process allows you to offer your own personal definition of the digital humanities, and some of those definitions have been published online.
(PS: when I was in grad school -- not that long ago! -- we all called it "humanities computing." Now, as a digital humanities administrator at a major research library, the question I hear most from colleagues outside the DH community is whether it even needs a name. Are these just the new humanities, the "new normal?")