The term most often comes into use when bemoaning the fact that there are no renaissance men left in the world. However, during the Renaissance, it was easier to be an expert in all fields, as the total sum of knowledge was considerably smaller than it is today. Since there is much more material to be known in any one field today, broad coverage at any sort of expert level is simply impossible. Similarly, in education there is the trend towards specialisation rather than a superficial knowledge of many fields.
See also: polymath