Rus' people
The name might be made of the roots Swede, Swedish rike - a kingdom or Latin rex, regis - a king and a suffix -aila, -ielo or a root of Prussian gailis - white, Lithuanian galas - phalos as by possibility in Ashurbanipal or English roots all, whole. The name coincides with his ruled lands - part of modern Russia, from Rus' people. His brothers' names were made following the same pattern: Skirgaila, Karigaila, Jogaila.