The loops of a knit are shaped so that they can open and close, and in the course direction they widen more easily than in the wale direction. That is why jersey and rib stretch more across the width. The stretch depends on the structure, the loop length and the yarn, and a fabric with elastane can stretch in both directions.
When cutting, you must know the stretch direction so that the pieces have the same orientation. In the pattern, specify where you want the greater stretch. For fitted pieces, choose a structure with good stretch across the width and reliable recovery.
stretchdirection
