Cycling specific socks are largely defined by the fit and the fabric. Given that cycling shoes are designed to be close fitting, cycling socks tend to be thin so as not to make the shoes uncomfortable. Equally, thicker socks are more prone to rub. Even winter cycling socks are pretty thin and rely on low-bulk warmth from materials such as merino wool.
While the aforementioned merino wool is a popular choice given it's breathability and odor resistance, most cycling socks use synthetic fabrics to deliver the desired combination of ventilation with sweat wicking  properties.
The final piece of the puzzle is good elasticity alongside a solid gripper - the last thing any cyclist wants is a pair of socks that won't stay up.