1510s, "gallery, portico, balcony," later "flat, raised place for walking" (1570s), from French terrace (Modern French terasse), from Old French terrasse (12c.) "platform (built on or supported by a mound of earth)," from Vulgar Latin *terracea, fem. of *terraceus "earthen, earthy," from Latin terra "earth, land" (from PIE root *ters- "to dry").
As a natural formation in geology, attested from 1670s. In street names, originally in reference to a row of houses along the top of a slope, but lately applied arbitrarily as a fancy name for an ordinary road. As a verb from 1610s, "to form into a terrace." Related: Terraced.