What is "reversion of series"

Reversion \Re*ver"sion\ (r[-e]*v[~e]r"sh[u^]n), n. [F. r['e]version, L. reversio a turning back. See Revert.]

1. The act of returning, or coming back; return. [Obs.]

   After his reversion home, [he] was spoiled, also, of all that he brought with him.
   --Foxe.

2. That which reverts or returns; residue. [Obs.]

   The small reversion of this great navy which came home might be looked upon by religious eyes as relics.
   --Fuller.

3. (Law) The returning of an estate to the grantor or his heirs, by operation of law, after the grant has terminated; hence, the residue of an estate left in the proprietor or owner thereof, to take effect in possession, by operation of law, after the termination of a limited or less estate carved out of it and conveyed by him.
   --Kent.

4. Hence, a right to future possession or enjoyment; succession.

   For even reversions are all begged before.
   --Dryden.

5. (Annuities) A payment which is not to be received, or a benefit which does not begin, until the happening of some event, as the death of a living person.
   --Brande & C.

6. (Biol.) A return towards some ancestral type or character; atavism.

   Reversion of series (Alg.), the act of reverting a series. See To revert a series, under Revert, v. t.