In general context, 'aperture' refers to how much light or substance can pass. Larger apertures mean more light. The room brightened as he opened the aperture of the window.
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Functional Diversity
'Aperture' is not limited to light; it can refer to any substance moving through an opening. The aperture of the pipe allowed water to flow freely.
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Specificity
An aperture is specific and often designed for a precise function or effect. The device's aperture was calibrated for optimal airflow.