She explains: "Communicating about weaving can be confusing at times. The same term can be used to describe more than one thing. For example, a balanced weave can mean the same number of weft picks as warp ends per inch . . . sometimes also referred to weaving square. It can also mean the same number of shafts up that are down . . . often related to counterbalance looms.
Then different terms may be used to describe the same thing. In the United States, we often see the term shaft used interchangeably with harness. As a young weaver, I was taught the shafts make up the harness; however, if anyone tells me they are weaving on a four harness loom, I still understand what they mean. But, the definition of the shafts making up the harness is important if you come in contact with draw loom weavers and they speak about weaving on double harness looms, which are looms with two sets of shafts."
Robyn's links will help clarify terms for beginning and experienced weavers.