1Masonry. Simple, smooth, or unadorned stone or stonework.
2Work of a plain or simple kind, as distinguished from ornamental work; specifically (now historical) plain needlework or sewing, as distinct from fancy-work or embroidery.
Origin
Late Middle English. From plain + work.
Definition of plain work in US English:
plain work
nounˈpleɪn wəːk
1Masonry. Simple, smooth, or unadorned stone or stonework.
2Work of a plain or simple kind, as distinguished from ornamental work; specifically (now historical) plain needlework or sewing, as distinct from fancy-work or embroidery.