Sunrise is the moment the sun's upper edge first shows above a flat horizon, the disc still bent up a little by the air.

Sol times it for the upper edge at a sea horizon with refraction included — the standard 0.833° below the geometric horizon, which is what almanacs print. Refraction lifts the sun by about its own width, so you see it a couple of minutes before it is geometrically there; a cold, dense morning lifts it more.

Sol times it for a sea horizon; a hill or a building across the street makes yours later.