Smocking

A short description comes from Wikipedia:

Smocking is an embroidery technique used to gather fabric so that it can stretch. Before elastic, smocking was commonly used in cuffs, bodices, and necklines in garments where buttons were undesirable.

Featured image: Smocking by Aspasia Bevilacqua.

Seeking the source for this image of a pleated apron:

Members of the guild who do smocking: (coming soon)

Smocking resources:

• Baroness Genoveva von Lübeck’s Honeycomb Pleatwork Apron Handout from honorbeforevictory.com – Comes with instructions and links.