Pinning is used whenever you use sewing pins to hold things in place.
Examples of where pinning is commonly used are:
- Pinning a seam in place before sewing it
- Pinning an ornament, pocket, or other part in place before attaching it
- Pinning darts or other pattern changes while fitting the garment on a model
Pinning is never permanent, but merely a temporary measure to hold things in place.
Pinning and basting are different techniques for similar situations