Opacities represent the degrees to which light is obscured by pollutant particles in the air.2. Having difficulty in understanding statements, presentations, or in explaining something: Students had difficulty in understanding the opacity of the teacher's scientific presentation.
The opacities of most dictionaries simply don't give people clear or straightforward definitions.3. Etymology: "darkness, obscurity", from French opacité; from Latin opacitatem, opacitas, "shade, shadiness"; from opacus, "shaded, dark".
2. On a radiograph, the phenomenon of not allowing the passage of electromagnetic radiation: Dr. Simpson complained about the opacity that the x-rays showed and wanted to have the process repeated.
3. Something that is obscure or incomprehensible: The authors hope that tbis dictionary is not characterized by opacity, but has clear and understandable definitions and example sentences.
Jim's math teacher was known for her opacity and his friends were all very frustrated, even after asking specific questions about the content of the lessons.