Backlighting in photography means just what it says
Backlighting means that the light is coming from behind your subjects and heading straight into the camera lens. Effectively this causes your family or friends to be silhouettes.
Often when looking and a view with the human eye, you look towards the sun and it appears as though everything is beautifully lit. This is especially true when asking people to stand in front of a landscape for a panoramic print, but can also occur when people are sitting on a bench or standing in a garden. To the human eye, there is a perception of light coming from all directions, making a perfect setting. As a photographer, you ask your subjects to stand in the sunlight unless of course you are striving to create a silhouette effect which in itself can create a memorable image.
To your eye, everything is bathed in sunlight
Often with the sun either behind your subjects or off to the side, their faces are in shadow. When taking your holiday snap you hardly notice that their features are obscured, it only becomes apparent when you view your images later. The best place for the sun to be located for any image is behind the photographers back, or slightly to the side and behind. This way, the light will be shining onto the faces of your subjects. Sometimes this causes people to squint a little but it they turn their faces slight to the side or gaze directly into the camera rather than the sun the end result will be well worth it. When you come to view your photos onscreen or have them printed, you will have a memorable image capturing the faces of the friends and family who shared the experience with you.