increasement

increase +‎ -ment

increasement (countable and uncountable, plural increasements)

1. (rare) An increase; growth.
2. (rare) An increment; an addition; augmentation.
   • 1662 Thomas Salusbury, Galileo's Dialogue Concerning the Two Chief World Systems, Dialogue 2:

     ... diminishing the velocity with decreasements like to the increasements acquired in the descent

• decreasement

• John A. Simpson and Edmund S. C. Weiner, editors (1989), “increasement”, in The Oxford English Dictionary, 2nd edition, Oxford: Clarendon Press, →ISBN.