What is "middle tenor"

Tenor \Ten"or\, n. [L., from tenere to hold; hence, properly, a holding on in a continued course: cf. F. teneur. See Tenable, and cf. Tenor a kind of voice.]

1. A state of holding on in a continuous course; manner of continuity; constant mode; general tendency; course; career.

   Along the cool sequestered vale of life They kept the noiseless tenor of their away.
   --Gray.

2. That course of thought which holds on through a discourse; the general drift or course of thought; purport; intent; meaning; understanding.

   When it [the bond] is paid according to the tenor.
   --Shak.

   Does not the whole tenor of the divine law positively require humility and meekness to all men?
   --Spart.

3. Stamp; character; nature.

   This success would look like chance, if it were perpetual, and always of the same tenor.
   --Dryden.

4. (Law) An exact copy of a writing, set forth in the words and figures of it. It differs from purport, which is only the substance or general import of the instrument.
   --Bouvier.

5. [F. t['e]nor, L. tenor, properly, a holding; -- so called because the tenor was the voice which took and held the principal part, the plain song, air, or tune, to which the other voices supplied a harmony above and below: cf. It. tenore.] (Mus.)

   1. The higher of the two kinds of voices usually belonging to adult males; hence, the part in the harmony adapted to this voice; the second of the four parts in the scale of sounds, reckoning from the base, and originally the air, to which the other parts were auxillary.

   2. A person who sings the tenor, or the instrument that play it.

      Old Tenor, New Tenor, Middle Tenor, different descriptions of paper money, issued at different periods, by the American colonial governments in the last century.