What is "gypsy scale"

The term Gypsy scale refers to one of several musical scales named after their association with Romani or stereotyped "Gypsy" music:

• Hungarian minor scale, minor scale with raised fourth and seventh degrees, also known as Double Harmonic minor scale.
• Hungarian Gypsy scale, minor scale with raised fourth but natural seventh. It is the fourth mode of Neapolitan minor scale.
• Phrygian dominant scale, also known as Spanish Gypsy scale.
• Double harmonic scale (major), the fifth mode of Hungarian minor, or Double Harmonic minor, scale.
• Ukrainian Dorian scale, also called Ukrainian minor scale.