A Tint is sometimes also called a Pastel. But to be  precise, Color Theory defines a True Tint as any Hue or mixture of pure colors with only White added.

A Tint lightens the color, but it doesn't make it brighter. Even though the color may appear brighter, in actual fact it is not. In other words, it remains exactly the same color, only a paler version. Furthermore, even a small amount of White added to a color, transforms it into a Tint.

Therefore a Tint can range from slightly lighter than your original color, all the way to White with barely any of the color mixed in.

In addition, a true Tint contains no Gray. 

To create a true Tint, simply add White to any individual color on the Color Wheel or any of those pure colors mixed together.

Regardless of this Color Theory definition, artists often bend the rules somewhat. Instead of White to mix a Tint, they use  other pale neutral pigments such as Titanium or Titan Buff. These pigment “Whites” can produce beautiful complex Tints.

Credit: Color Wheel Artist