A holosign was a sign that was represented by a hologram. It would display usually static text or images, but had the capability of updating.
In 22 BBY during the Clone Wars, a huge holosign was hanging in the air above Customs Central on Aargau read "WELCOME TO AARGAU, JEWEL OF THE ZUG SYSTEM! OBSERVE THE FOLLOWING RULES."
In 16 ABY, a holosign hung ornately over the doors of the Senate Building's Grand Convocation Chamber by Tolik Yar read "882 DAYS WITHOUT A SHOT BEING FIRED IN ANGER. Remember, Peace Is No Accident."
In 22 BBY during the Clone Wars, a huge holosign was hanging in the air above Customs Central on Aargau read "WELCOME TO AARGAU, JEWEL OF THE ZUG SYSTEM! OBSERVE THE FOLLOWING RULES."
In 16 ABY, a holosign hung ornately over the doors of the Senate Building's Grand Convocation Chamber by Tolik Yar read "882 DAYS WITHOUT A SHOT BEING FIRED IN ANGER. Remember, Peace Is No Accident."