round character
a character, who is capable of surprise, contradiction, and change [through development]; they are representations of human beings in all of their complexity. A term coined by E. M. Forster in Aspects of the Novel (1927) in opposition to a flat character. Forster’s aim is not to elevate the round at the expense of the flat, although he admits that the round is on the whole always a more interesting creation. Instead, he argues that there are compelling artistic reasons for a novelist to employ flat characters. And there are unquestionably great novelists, such as Dickens, who use only flat characters. (eForeword 2002) Also see flat character