The story
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: Having a shifting (mobile) accent that falls on the root (alternatively, the first or penultimate syllable of the stem) in the direct case-forms, and on the suffix (alternatively, the ultimate syllable of the stem) in the weak case-forms. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.