ONLINE GLOSSARY
0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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• Adjacent View. A view that is located to the side of, directly above, or directly beneath another view.
  
  
• Arc. A portion of the circumference of a circle.
  
  
• Arrowheads. Directional marks in the shape of the tip of an arrow, used either to indicate the distance between two points on a dimensioned working drawing or as a pointer to specify a particular object in a drawing.
  
  
• Auxiliary Plane of Projection. A special plane arranged so as to be parallel with a non-principal plane or surface in order to project an auxiliary view. When any plane or surface on an object is not parallel to a principal plane of projection, it is a non-principal plane and will therefore not appear true size in the corresponding plan views. An auxiliary plane of projection is set up in order to create a true-size view of such a non-principal surface.
  
  
• Auxiliary View. A true-size view of a non-principal plane or surface projected from an auxiliary plane of projection. When any plane or surface on an object is not parallel to a principal plane of projection, it cannot be depicted as true size in the corresponding normal plan views. Such a plane or surface can only be depicted true size by creating an auxiliary view.
  
  
• Axes of Motion. The three dimensions about which motion can occur. Labeling for each axis often depends on the context or subject. For objects such as vehicles, the three dimensions may be described as longitudinal (fore-aft), lateral (side to side) and vertical (up-down). Longitudinal and lateral motions often correspond with the "x" and "y" axes of a two-dimensional plane. In this case, the "z" axis represents the third or vertical dimension. See also Geometric Center.
  
  
• Axes of Rotation. The three dimensions about which an object can rotate. Labeling for each axis often depends on the context or subject. For aircraft, the three axes are pitch (rotating upward or downward about the lateral axis), roll (rotating or "banking"left or right about the longitudinal axis) and yaw (turning or "pointing" to the left or right about the vertical axis). See also Geometric Center.
  
  
• Axis of Rotation. One of the three dimensions about which an object can rotate. See Axes of Rotation.
  
  
• Axis of Symmetry. The "dividing line" or centerline about which an object is symmetrical. Features on either side of the axis of symmetry will be a mirror image of each other.

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0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Click on a letter to browse through the Glossary terms.
To download a printable version of the entire Glossary, click here.

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Reproduction, in whole or in part, is prohibited without written permission from the publisher.