The answer to 'what is skylight' is a window installed in the roof or ceiling of a building to let in natural light. Skylights come in a variety of shapes, sizes, and materials, and can be fixed or operable to allow ventilation. They are a popular way to brighten up interior spaces and reduce the need for artificial lighting during the day.
Skylights are typically made of glass or a durable plastic material like acrylic or polycarbonate. They are installed by cutting an opening in the roof and securing the skylight frame in place. Proper installation is important to prevent leaks and ensure the skylight is weathertight. Skylights can also come with features like tinted or coated glass, remote-controlled operation, and built-in shades or blinds.