The rule of thirds is a technique used to place subjects in a photograph. Photographers follow the rule of thirds when they place their subject in a place other than the center of the picture.
This is the basic principle that is the most valuable to a new photographer. This rule takes our rectangular shape and divides it into thirds. The key elements or objects in a composition should fall on one of these thirds lines. The one point on our photograph where the viewers' eye comes to rest should fall on one of these lines where both a horizontal and a vertical line come to rest.
An air management technique. Use a third of the tank to get to your destination, a third to get back, and the last third belongs to your buddy in case of an emergency.
The rule of thirds is a design strategy that breaks up any scene (image) into three rows and three colums (9 cells). Placing your main subject at the intersection of the rows and colums usually helps to form a strong composition. The horizon line also benefits from an understanding of this rule. If you place the horizon line in either the top third (emphasizing the ground) or the bottom third (emphasizing the sky) you tend to get a stronger composition.
A composition guideline that suggests putting the center of interest at the crosspoints of two vertical and two horizontal lines that divide the frame into three equal segments.
A guideline for where to place the subject in two dimensional art. Divide the media into three imaginary rows and three imaginary columns of equal width. There will be four points of intersection. Placing the subject on one of these four intersection points is the rule of thirds.
Composition rule that divides the frame into nine equal areas. Subjects could be placed along one of the lines or at an intersection.
Composition rule stating that a scene is most appealing to the eye if its primary elements appear at certain points on the screen. It divides the screen into thirds vertically and horizontally, like a tic-tac-toe game, and places important elements wherever the imaginary lines intersect.
Composition technique that places important subjects or objects on the lines, or at the cross points, in a tic-tac-toe pattern imagined over the viewfinder.
A basic photographic "rule"
This is more of a guideline than a rule. It's a guideline for composition that says that the dominant points of interest should be situated about 1/3 of the way into the image. For example, a horizon looks best 1/3 from the top or bottom of an image, not right in the middle. A tree should be about 1/3 from the side of the frame.
the rule of basic photographic composition which states that vertical and horizontal lines should split the picture up into thirds not halves. A horizon, for instance, should be positioned either in the top or lower horizontal third of the picture - not half way. And vertical subjects, such as a building or a person, should occupy the right or left third - never the centre.
The rule of thirds is a compositional rule of thumb in photography.
In scuba diving, the rule of thirds is a rule of thumb that divers use to plan dives so they do not consume all the breathing gas from the diving cylinder before the end of the dive.