Parisian stitch
Parisian stitch is a longer horizontal/vertical stitch used in needlepoint next to a smaller parallel stitch to create a basketweave pattern. The end points on either end alternate in a staggered pattern.
According to Thérèse de Dilmont in the Encyclopedia of Needlework:
The case holding this thread is commonly known as an etu and is derived from the French word meaning fabric case.
