Reciprocal

Loosley meaning ‘in return’, based on the stricter mathematical sense of the word, found in financial and scientific theories, where reciprocal refers to the number or fraction which when multiplied by a specified other number or fraction will produce the number one. For example a half is the reciprocal of the number two; and a fifth is the reciprocal of the number five. The word derives from Latin ‘re’ (back) and ‘pro’ (forward).-