Deflector shield

Deflector shields, also called energy shields or just shields were translucent or transparent energy fields designed to protect vehicles, spacecraft or even entire cities and planets from attacks. A structure known as a shield generator was required to project it. Shields required a constant flow of power to operate.

Types
Two main types of shields existed. The first one, known as the ray shield was capable of protecting against energy-based projectiles but barely had any effect on solid ammunition or units. The second type, the particle shield was designed to counter solid hazards, such as asteroids, missiles or units. Larger ships or structures often wielded both kinds of shields, but lighter units usually spared the latter. Ray shields could sometimes be fatal to organic beings due to their massive energy.

Usage
Some Kaminoan cities, such as Sigirum City were known to utilize shields to protect against the violent climate, while Mustafarian mining stations defended themselves from the fiery lava with particle shields. Nearly all spacecraft in the galaxy possessed some kind of shielding; notable exceptions included early TIEs. Some particularly wealthy worlds like Coruscant made use of planetary shields.