2. Prefix. Used to form terms related to the diaphragm. ¹
¹ Source: wiktionary.com
Medical Definition of Phreno-
1. Phren-phreni-phrenico- The diaphragm; the mind; the phrenic nerve. Origin: G. Phren, diaphragm, mind, heart (as seat of emotions) (05 Mar 2000)