- If you are looking for the beverage from the re-imagining, it is spelled ambrosia.
Ambrosa (note the spelling) is an expensive alcoholic intoxicant, typically green in color.
It's rarity makes its valuable amongst the survivors; Starbuck imagined being rich after finding the many storage bins filled with ambrosa on Proteus. Were it not for the Cylons attack on Proteus, he would be quite wealthy. (The Long Patrol)