Reciprocally \Re*cip"ro*cal*ly\, adv.

1. In a reciprocal manner; so that each affects the other, and is equally affected by it; interchangeably; mutually.

These two particles to reciprocally affect each other with the same force. --Bentley.

2. (Math.) In the manner of reciprocals.

Reciprocally proportional (Arith. & Alg.), proportional, as two variable quantities, so that the one shall have a constant ratio to the reciprocal of the other.

Source: Webster's Revised Unabridged Dictionary (1913)