"reciprocal" - key terms from Wikipedia

reciprocal
reciprocal	agreement
reciprocal	altruism
reciprocal	basis
reciprocal	beneficiary
reciprocal	frame
reciprocal	inhibition
reciprocal	innervation
reciprocal	lattice
reciprocal	lattice vector
reciprocal	recording
reciprocal	recording studios
reciprocal	relations
reciprocal	rule
reciprocal	space
reciprocal	square
reciprocal	teaching