Elijah Meeks and Karl Grossner’s "four expressions of digital humanities" remains a model definition of what DH is, and what it can be:
Meeks and Grossner, The Journal of Digital Humanities: v. 3, no. 1, Summer 2012
These four active definitions encompass the broad range of current practices in the digital humanities. The interdisciplinary nature of the field, however, increasingly leads scholars and practitioners to new and evolving expressions. As Meeks and Grossner advocate,"the boundaries between these are fluid; in particular, some products of digital humanities scholarship blur the line between archive, tool, and publication." A recent increase in academic and public interest in the field has lead to the need for evaluation of current work, leading to the creation of guidelines for assessing DH work from the Modern Language Association.
The term "digital humanities" refers to scholarship and practice in the field, an area of study that can be traced concurrently with the rise of 20th century computer engineering. Originally called "humanities computing," foundational work in the discipline is commonly attributed to Father Roberto Busa of Italy in the late 1940's. Following an increase in computing centers in the 50's and 60's (such as the Centre for Literary and Linguistic Computing at Cambridge), the relative accessibility of early personal computers opened the door for new approaches to traditional textual scholarship. As pedagogy shifted and consolidated through the 1970's, digital humanists (or "dhers") expanded their practice worldwide to encompass data mining, software design, and more. The increase of scholarly communication through academic conferences, publications, and professional associations built a legacy that field researchers carry forward today with the support of the National Endowment for the Humanities and similar international counterparts.
For more information on the history of the Digital Humanities, read A Companion to the Digital Humanities.