Exposure, Aperture and Shutter Speed explained simply with thanks to:
"Photography Mad.Com Tips and Tutorials"

Great definitions for beginners

Aperture works like the human eye and changes diameter from a wide aperture which lets in lots of light, to a narrow aperture which lets in less light. Diameter is measured by an 'f-number' (focal length). F-numbers are spaced one stop apart and by moving one f-stop you either double or halve the amount of light the aperture admits, meaning you need to either halve or double the shutter speed to keep a constant exposure. The wider the aperture, the lower the f-number
  • A wider aperture decreases the depth of field (amount of the scene which is in focus). While this is fine (and often desirable) for portraits and close-up photos, it usually doesn't work so well for landscapes.
  • As shutter speed gets slower, motion blur becomes more apparent. This can either be blur from a moving object, or camera shake if you are hand-holding your camera.
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The faucet analogy for understanding aperture
AV ( Aperture Priority) The higher the F number, the more of the photo that will be in focus.

Bokeh  clear explanation   aesthetically pleasing background in a photograph for effect - 7 quick tips for creating Bokeh

Depth Of Field is the amount of the scene which is in focus
Explained clearly in the following video

Exposure  The basics

Exposure is a combination of two fundamental camera settings - aperture diameter and shutter speed. Exposure is the amount of light that reaches the camera's sensor. A perfect exposure captures the right amount of light without losing detail in the highlights or shadows.

Exposure Compensation makes sure the photo is not underexposed (too dark) or overexposed (too light or white)

Exposure value (EV) is the exposure settings on your camera for a particular combination of light value and ISO.

Focal Length of a given lens determines the size of the recorded image on your digital sensor. Generally, the longer the focal length of the given lens, the larger the subject will be in the image.  A lens with a focal length of 100mm, will produce an image with the subject twice as high and twice as wide as the subject produced in an image with a 50mm lens.  Likewise, a lens with a focal length of 400mm will produce an image with the subject four times as high and wide as the subject produced in an image with a 100mm lens. source:

Hyper Focal Distance Focusing your camera at the hyperfocal distance ensures maximum sharpness from half this distance all the way to infinity

HDR ( high dynamic range) is a process which creates an image from at least 3 separate shots, each with a different shutter speed (exposure). The 3 images are then blended together into one photograph, using a software program. Photomatix Tutorial
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Illumination is the amount of light falling on the subject

ISOWhat is ISO speed ?  well explained.  General rules for ISO choices

Light value (LV) is a measure of the luminance of a scene. It refers to how bright the subject is.

Linear composition - 3 main types of linear composition: The grid, diagonals and curvilinear - the lines guide the eye and frequently the lines intersect to provide balance. In the case of curvilinear, the composition flows

Luminance is the amount of light reflecting off of the subject

Panning  involves moving the camera horizontally to follow the moving subjectusing a slower shutter speed.  Move your camera at the same speed of the object, to keep the subject sharply in focus, with a blurred background.  Good for artistic effect and to convey motion in your image.

Prime lenses - a lens that has one focal length only, ranging from wide angle ones through to the longer telephoto ones.
Prime or zoom - which is best ?

Shutter speed is simply a measure of how long the camera's shutter is open, ranging from anywhere around 1/1000th of a second, to several seconds. The trick is to select a shutter speed which allows you to capture enough light without blurring the subject

Silhouette is a view of an object or scene consisting of a background with an outline of a silhouetted object usually beingblack

Tilt and Shift This artistic photographic technique can be used to blur the viewer's gaze and direct it away from parts of the image the photographer wishes to de-emphasize. The depth of field of the image is altered. The technique can be used to create fake miniatures of real life objects.

Tonal Range is the region where most of the brightness values are present

Zoom (Digital versus Optical) Digital zoom digitally enlarges part of the image,  merely cropping out a smaller section of the image, with a noticeable loss in image quality. 
Optical zoom is when the camera actually brings the lens physically closer to the subject,  actually magnifying the image with the lens.  Using optical zoom enables you to get closer to the subject without loss of detail or image quality.