Ask Tom: What's the difference between words dawn/sunrise and dusk/sunset?

There is, but there can be confusion, so let's provide some definitions: "Twilight" is the period after sunset, or before sunrise when all or part of the sky is illuminated by reflected sunlight, though the sun itself is not visible above the horizon. The term "dawn" is synonymous with the start of morning twilight. "Sunrise" occurs the moment the disc of the sun peeks above the eastern horizon due to the Earth's rotation. "Sunset" is the opposite. It occurs the moment the disc of sun completely disappears below the western horizon. Technically, "dusk" is the period of twilight between complete darkness and sunrise (or sunset). In common usage, "dawn" refers to morning, while "dusk" refers only to the evening twilight.