| Word | Description |
| In-the-ditch quilting | the process of quilting just next to the seams on a quilt. This is also called stitch- in-the-ditch. Generally you will stitch on the side of the seam that does not have the seam allowances behind it. The side with the seam allowances stands above the other side of the seam. And the idea is to sew on the lower side, hence in the ditch. |
| Inset seam | The type of seam that joins a piece of fabric into an angled opening between two other pieces of fabric that have already been joined. |
| Ironing | moving a hot iron while it has contact with fabric. Often ironing can stretch and distort fabrics and seams. A better alternative is to press, where you just lay the hot iron down and lift straight up from the fabric. |
| Isosceles triangle | a triangle that has two equal sides. The witch in this Witch Block has 4 isosceles triangles in it her hat, her face and the two hair triangles. |