Hologram

"Help me, Obi-Wan Kenobi, you're my only hope *static* Help me, Obi-Wan Kenobi, you're my only hope."

- Leia Organa's message to Obi-Wan Kenobi

A hologram was a visual projection of a person or object, generally used for communication or entertainment purposes.

Members of the Jedi Council dispatched to missions on remote worlds could regularly participate in Council meetings held at the Jedi Temple by appearing as holograms.

Holographic technology was sophisticated enough, that a holographic image could be made to project a smaller holographic image, as in the case of a holographic image of R2-D2 projecting a message of Princess Leia.

After the Battle of Endor, hologram technology became advanced enough that the user could be seen in full color without scan lines. Supreme Leader Snoke of the First Order was known to utilize this kind of hologram when speaking with Kylo Ren and General Hux, while the two were on Starkiller Base.