Monochromatic photography means exactly what it sounds like. Just one color. By picking different shades of the same color, you can highlight different areas of your photographs. Monochromatic photography is a great technique to isolate individual colors and make them really stand out!

Here is an example of a Monochromatic photograph:

photo by bgottsab

Here is another example of a Monochromatic photograph:

This photograph uses only oranges and reds to create a monochromatic photograph!

Obviously this technique is really useful and can make your photos really pop when done well.

See also:
Color & Perspective
Color Simplicity
Color Tinting & Shading In Photography
Analogous Colors
Complementary Colors
Color Wheel
Color Psychology In Photography
Color Balance and Highlight

Learn more:
Learn how to become a better photographer.
Learn more about color in Photography.
You can also learn from the Masters Of Photography here.
More photography resources.