Sewing Definitions — stitches, seams, quilting and sewing terms from Apparel Search
In sewing, to tack or baste is to make quick, temporary stitching intended to be removed. A basting stitch is essentially a straight stitch, sewn with long stitches and unfinished ends. Tacking holds a seam or trim in place until it can be permanently sewn, usually with a long running stitch made by hand or machine called a tacking stitch or basting stitch. It also attaches a lace collar, ruffles or other trim temporarily so the article may be removed easily for cleaning or to be worn with a different garment, and it transfers pattern markings to fabric with a special loose looped stitch called a tailor's tack.
External references

Learn more about sewing.
| The above article is licensed under the GNU Free Documentation License. From Wikipedia, the free encyclopedia (https://en.wikipedia.org/wiki/tack_(sewing)). 7/4/09 Above article modified by Apparel Search |
Tacking is the one kind of sewing designed to be undone. Its stitches are long, its ends are left unfinished, and its thread is often a contrasting colour chosen so the stitching is easy to see and easy to pull out. What tacking buys is control. Fabric layers shift under a machine's presser foot, curves ease unevenly, and slippery fabrics creep; a line of basting pins the situation still while permanent stitching is done accurately beside it. Professional tailoring basts extensively, fitting a garment on the body in basted form before any seam is final, because a basted seam can be moved in seconds and a machined one cannot.
The uses divide into three. First, holding: tacking temporarily holds a seam or trim in place until it can be permanently sewn, and basting holds sandwiched pieces of fabric in place in quilting, where three layers must not shift against each other during the long work of quilting them, and in embroidery, where fabric must sit flat in its frame or on its stabiliser. Second, temporary attachment for use, not for making: a lace collar, ruffles or other trim tacked to a garment can be removed easily for cleaning, or worn with a different garment, and for this purpose tacking stitches are sewn by hand so they are almost invisible from the outside. Third, marking: tacking transfers pattern information, dart points, fold lines and matching points, from paper to fabric in thread that survives handling in a way chalk cannot.
Hand basting uses the longest form of running stitch, several stitches loaded on the needle at once, worked without knots that would mark the fabric; a knot or a few backstitches at the start, if used at all, stay in the seam allowance. Machine basting uses the machine's longest stitch length, often with loosened tension, so the thread pulls out in one strand when the work is finished. In both cases removal is part of the technique: basting is pulled out after permanent stitching, never stitched over permanently where its removal would be blocked, and contrasting thread prevents the embarrassing survival of a basting line in a finished garment.
Terminology crosses the Atlantic in this corner of sewing: tacking is the common British term and basting the common American one for the same temporary stitching, and both appear throughout sewing literature. The tailor's tack preserves the older sense of tack as a marker, a loop of thread left standing on the fabric as a signpost. Together with its relatives in this section, the running stitch it is built from and the seams it prepares, tacking represents the preparatory half of sewing: the unglamorous, removable stitching on which the accuracy of all the permanent stitching depends.
To tack or baste is to make quick, temporary stitching intended to be removed. The stitching holds pieces, seams or trim in place until they can be permanently sewn, or for as long as a temporary attachment is needed.
A basting stitch is essentially a straight stitch sewn with long stitches and unfinished ends. It temporarily holds sandwiched pieces of fabric in place, often in quilting or embroidery, and is removed after the piece is finished.
A tailor's tack is a special loose looped stitch used to transfer pattern markings to fabric, or otherwise mark the point where two pieces of fabric are to be joined, without chalk or pins that might shift.