A word for forward/backward movement
I've come to understand that lateral and sideways can be used when moving a forward-facing object from one side to another (and eventually back again).
Is there a common word for forward and backward movement, without specifying which?
Example:
A car cannot make lateral movements, only {forwards and backwards}.
(I hope I am using lateral correctly; please point it out if not.)
Solution 1:
Axial would come closest. It can mean "along the axis (of an object)".
If something can only move forwards or backwards, or the direction doesn't matter in general, then the movement is simply a movement. No attribute required.
The orientation of the object (e.g. forward-facing) doesn't matter by the way because lateral is relative to it (or you).
Solution 2:
The word you're looking for is longitudinal. (Wikipedia: Aircraft Principal Axes)
Which is defined as: (Google: define longitudinal)
- running lengthwise rather than across
For surface movement, lateral and longitudinal are perpendicular. To create 3D movement just add the vertical axis for vertical movement. This axis is also needed to describe left and right rotation, or yaw. (Wikipedia: Yaw Rotation & Road Vehicles)
Therefore your original example becomes:
A car can only move longitudinally (forward & backward) with varying amounts of yaw (turning left and right), and is incapable of moving laterally (left & right) in normal operating conditions.