Definition
If you look at the core offering there is little difference in the functions between S60 and latest gen Smart OS's, it is just that today's standards are refined to provide productivity, intelligence and performance. Application intelligence should not be confused with "smart" in smartphone.
http://www.oxforddictionaries.com/definition/english/smartphone
smartphone
noun
a mobile phone that performs many of the functions of a computer, typically having a touchscreen interface, Internet access, and an operating system capable of running downloaded apps.