The world of Shannara is initially described as post-apocalyptic. The Great Wars are first mentioned in The Sword Of Shannara, where Allanon re-tells the past history of the world to the Ohmsford brothers. Also he mentions that the Druids of old (First Druid Order) were initially trying to recover old sciences, not magic.
The next link is the robotic monster that attacks the party on the way from Culhaven to Paranor. It clearly hints that the creature is based on the old world's artificial intelligence.
In the third book, The Wishsong of Shannara, it is hinted that magic may be gone and replaced by something else, possibly by the sciences of old. However, that never happened.
In the Voyage of Jerle Shannara trilogy, we see another AI monster of the old age named Antrax, which is described as a very advanced supercomputer capable of self-maintenance and creating cyborg-like creatures (wronks) out of living things
The Word is first mentioned in the original Shannara novels by The King Of The Silver River, stating that The Word has created this world.