Let's start with some non-scientific definitions of color.
Red is hot and spicy, like standing too close to the fire.
Orange is warm and smooth, a velvet curtain heated by the sun.
Yellow is buttery and rich, like sunshine on your face.
Green is earthy and comforting, the smell of fresh pine needles.
Blue is cool and crisp, like dipping your foot in a lake in October.
Purple is dark and rich, a baritone sax bellowing jazz.
Brown is healing and ancient, the smell of earth on the forest floor.
Just my attempt.
Here are definitions of the color terms you'll encounter.
Rather than placing them in alphabetical order, the terms are grouped with similar terms.
Hue is another word for color.
Saturation is the amount of gray in a color.
Think of it as being the vividness/richness of a color.
Luminosity is the brightness of the tones.
Think of it as being the black-and-white component of color.
Contrast is the relationship of the tones in a photograph.
When contrast is low, the whites are grayish and the blacks are also grayish.
When contrast is high, whites are more purely white and blacks are purely black.
A color model describes the colors we see.
The model distributes numerical values for color in three dimensions to represent the visible spectrum of color.
A color space shows the gamut of colors that can be produced using a particular color model.
Whereas a color model determines the relationship between color values, a color space defines the those values as being certain colors.
Go to RGB Color.