Most floor-length nightgowns have a relaxed or oversized fit. Some listings note they run large and recommend sizing down if you’re between sizes.
Common materials include polyester, a 95% rayon / 5% spandex blend, and some cotton options (often poplin).
Common extras include side pockets, button-front or half-button plackets, and some styles with full-length zippers for easy on/off.
Many listings describe full-length gowns that cover from neck to ankles; some styles are noted as calf length for a slightly shorter fit.
Listings show sizes from small and medium up through plus sizes, including XXL and XXXL.