Solar sail is a propulsion technology based on light reflection.
A star or some other light source provides thrust through absorption or reflection of photons (so-called radiation pressure) by a large sail fitted onto the starship.
An interesting feature of solar sail technology is that the radiation pressure decreases proportionally to the gravity of the star, meaning that theoretically the provided thrust remains identical regardless of the distance to the star. An advantage over other methods of propulsion is that solar sail does not require fuel of any type to operate.
The Bajorans used solar sail powered lightships as early as the 16th century, until as late as the 21st century.