principal axis (noun)

1. In the cinema, the principal axis is utilized to achieve precise focus and clarity in the camera lenses.

2. During the time of Galileo Galilei, the experiment with lenses and optics established the concept of the principal axis.

3. The author vividly described the rainbow in his novel, mentioning the principal axis of light passing through the droplets.

4. The architect strategically positioned the windows along the principal axis of the building, allowing for optimal natural light distribution.