www.alphadictionary.com

A nice short word that probably has too many meanings for the Doctor to want to tackle it.

1. As a verb, to attach or fasten; as a noun, the object used to make the fastening; generally associated with woodworking. A tack in sewing is also a quick attachment.

2. In sailing, the direction of the vessel with respect to the wind, also the action of setting that direction.

3. The harness for a horse, kept in a tack room when not in use.

4. A component of the word hardtack, an edible and durable food.

In sewing, what would be the difference between tack and baste? I've always used baste as a quick sew job, to simply hold things in place until the real sewing can be done. Where does tack fit in here?

"Tack", in sewing, is one stitch tied off at a single point. Baste is continuous. Tacks might be used to stabilize trouser cuffs, for example.

So basting is 'multi-tacking', eh?

Nope. "Multi-tacking" would presume that each stitch is solidly tied off. Basting implies that the thread is free to be pulled out completely from any point along the seam. Basting is often used as a temporary measure to fix a difficult join into place before putting in the final seam; that's why the basting thread should be easy to remove.