D defs.my
Entry 2 senses Webster, 1913

Reciprocally

/(rē̇*sĭp"rō̇*kal*ly̆)/ · Re·cip·ro·cal·ly · IPA
01 adv. In a reciprocal manner; so that each affects the other, and is equally affected by it; interchangeably; mutually.
  1. 1.
    In a reciprocal manner; so that each affects the other, and is equally affected by it; interchangeably; mutually.
    “These two particles do reciprocally affect each other with the same force.” Bentley.
  2. 2.
    In the manner of reciprocals.(Math.)
Phrases & compounds
Reciprocally proportional — proportional, as two variable quantities, so that the one shall have a constant ratio to the reciprocal of the other.