Flash

[1] The first stage of the drying process of paint where most of the solvents evaporates.
[2] A sudden burst of energy.
[3] When crude oil is heated the lighter or more volatile vapor is separated and travels to the top of the tank. This travelling is called flash.
[4] The impact of electric arc rays against the human eye.
[5] The fin of surplus metal formed at the seam of a resistance weld.
[6] To use your signal lights as in "My car was flashing left".
[7] To rapidly switch the headlights off and on — usually to indicate a warning. If you are behind someone and you flash your headlights, it means that you want him to pull over so you can pass. If you see someone flashing his lights, it could mean that there is a police car ahead so slow down; or it could mean there is danger ahead (e.g., deer on the road, an accident ahead, etc.).