Crumbs are slang for small scraps of fabric. There’s not set size for a crumb but I think any scrap less than 4″ fits into this category. Some folks define this as any piece of fabric less than 2″. (That’s really small!)
Crumbs and strings (long strips of scrap fabric) can be used for projects rather than tossing them into the garbage. This is a great way to save money on fabric and be part of the recycling/reuse movement. Many quilters have published books and videos featuring scrap quilts using crumbs. Check out this YouTube channel – Conquering Mount Scrapmore with Brenda – for lots of ideas on using crumbs in your projects.