The 1970s mid-to-late 1970s
The Jumpsuit
Trousers and a top built as one continuous garment, no waist seam breaking up the silhouette at all - a single piece that could carry a woman from a disco floor to a dinner reservation without a second thought.
The jumpsuit fuses a fitted or wide-legged trouser directly to a bodice in a single continuous garment, eliminating the waist seam that would otherwise separate a top from a bottom entirely. That construction choice does real practical and visual work at once: no waistband to gap or ride up, no tucking-in required to keep a look clean, and a genuinely unbroken vertical line running from shoulder to ankle that a separate top-and-trousers combination simply can't replicate.
That clean, unbroken line is exactly what made the jumpsuit such a natural fit for the disco silhouette - cut from slinky, body-skimming jersey or dressed up in lurex for evening, a jumpsuit moved as freely as loose trousers while reading as considerably more polished and considered than an ordinary separates outfit. Halston worked the shape repeatedly through the decade's second half, and it became a genuine Studio 54 staple precisely because it let a woman dance all night in something that still looked deliberately put-together rather than simply practical.
I think the jumpsuit is worth its own entry specifically because it collapses two ideas this section usually treats separately - eveningwear glamour and genuine ease of movement - into a single garment that manages both without compromising either. Few other pieces from this decade let a wearer go straight from a dance floor to essentially anywhere else without a costume change, which is a real practical achievement dressed up as pure disco glamour.