Call me an Idiot but what defines a solo carry
I know that
and
are solo carries. But what makes them solo carries? I really wanted to know because I made a thread about how some people were complaining about the overly team oriented status of the game, and how people should come up with concepts so that Riot would maybe follow player concepts like they did with Solar and Lunar Eclipse Leona. I want to contribute, but first I need to know what makes a solo carry a solo carry and design skill concepts accordingly.
Basically tell me how solo carries are solo carries!
Jungle:
Mid:
ADC: 
.. even if u land a spear.. even with 30 kills pouncing into a 1v5 your going to be dead before u hit the ground...