trans·thoracic \¦tran(t)s, -raan-, -nzˌ\adjective Etymology:trans- + thoracic 1.: performed or made by way of the thoracic cavity 2.: crossing or having connections that cross the thoracic cavity < a transthoracic pacemaker > • trans·tho·rac·i·cal·ly\-¦rasə̇k(ə)lē \adverb