An expression applied to the convolutions of wire in a solenoid,
electro-magnet, or other apparatus or construction of that kind. A turn
indicates a complete encircling of the core or axis of the object. Thus
a wire wound five times around a bar gives five turns.

While this is its primary meaning the term if compounded may refer to
virtual turns. Thus an ampere-turn means one ampere passing through one
turn. But ten ampere-turns may mean ten amperes passing through ten
turns, five amperes passing through two turns, and so on. This use is
analogous to a dimension of length in a compound word, as foot-pound.

[Transcriber's note: "But ten ampere-turns may mean ten amperes passing
through ONE turn or one ampere through ten turns, and so on."]

There may be a number of kinds of turns qualified by descriptive
adjectives, as series-turns, the turns of wire in a series circuit of a
compound dynamo. In the same way there are shunt-turns. If series
ampere-turns or shunt ampere-turns are meant the word ampere should be
included.