thereon 1924 - epigrapho {ep-ee-graf'-o}; from 1909 and 1125; to inscribe (physically or mentally): -- inscription, write in (over, {thereon}).
thereon 2026 - epoikodomeo {ep-oy-kod-om-eh'-o}; from 1909 and 3618; to build upon, i.e. (figuratively) to rear up: -- build {thereon} (thereupon, on, upon).