No, they're not the same thing.
A (R/C) servo has a built-in controller and is driven by a simple single line pulse position modulation signal at around 50Hz. They are not capable of continuous rotation, but can be positioned to a reasonable degree of accuracy to a given angular displacement.
A servo usually contains a DC motor.
A DC motor needs to be driven by a pulse-width modulation signal at a much higher frequency, and needs at least two signal lines, one for speed and one for direction.
It is usually capable of full rotation, but not accurate angular displacement.