A structure that folds and unfolds in sections. Everything stays present; only what is opened is shown.
German Akkordion, coined in 1829 by inventor Cyrill Demian from Akkord (chord, harmony), itself from French accord, from Latin ad- (to) + cor (heart); named for the instrument's chords, and the bellows shape gave English the sense of anything that folds in pleats.
A structure that pleats closed and opens again, everything kept present, only what is opened shown.