Mobile learning is increasingly seen as a boon to universities and educators as a means of enabling learning anywhere, anytime and at the convenience of the learner. Even though the field of mobile learning is in its infancy, there is no common understanding of what mobile learning is. Previous attempts at defining mobile learner have either been overly inclusive or exclusive, and have focused on characteristics of the mediating technology, the learner, or the nature of the learning activity. Inspired by Wittgenstein's theory of family resemblances, this paper explores the attempt to create a new definition of mobile learning that will be dynamic, drawing from a collection of characteristics that may change over time rather than just supplying a single, unchanging definition. The revised definition will be used to support the development of a Mobile Learning Evaluation Framework by clarifying the attributes and features to be included in a robust and flexible definition of mobile learning. The outcome may be of value to researchers in the mobile learning field and educators considering incorporating mobile learning initiatives into current pedagogical strategies.