Tint, shade and tone

Tint is a lighter version of a colour obtained by mixing the colour with white, to increase Lightness.
Shade is a darker version of a colour obtained by mixing the colour with black, to increase darkness.
Tone is the saturation adjusted version of a colour obtained by mixing the colour with grey of the same lightness, or by applying both tint and shade.

Note that tint and shade adjust the lightness of a hue, and tone adjusts the saturation of a hue.
In the HSL model, mid lightness value corresponds to the normal version of the colour, with tinted colours increasing and shades decreasing the lightness, and tone adjusting the saturation.

In common speak

Commonly speaking, shade of a colour can refer to either the adjustment of

Examples

Pastel colours are generally tinted colours.