While there is a substantial conceptual literature on equality in education, there has been little clarificatory discussion on the term equity, despite its frequent use in policy and planning documents. The article draws out some different ways in which equity can be understood in education. It distinguishes three forms of equity, looking at the social context when major shifts in the meaning of the term took place in English--the fourteenth century, the sixteenth century and the eighteenth century. Terming these equity from below, equity from above, and equity from the middle, the analysis highlights how each helps clarify aspects of the concern with diversity within the capability approach. The conclusion drawn is that all three forms of equity need to be placed in articulation to expand capabilities in education.