In J.R.R. Tolkien’s mythology, Ent comes from the Old English word ent, meaning giant.
Tolkien used the term for the ancient tree-shepherds of Middle-earth. The word appears in Old English literature, including the compound enta geweorc, commonly translated as “the work of giants,” in the poem Beowulf. Tolkien’s knowledge of Old English allowed him to transform that historical word into a distinctive people in his fiction.
The Ents appear most prominently in The Two Towers. Treebeard, or Fangorn, is their best-known representative, and the Ents hold an Entmoot before deciding to attack Isengard. Their action responds to Saruman’s destruction of forests and use of the trees as industrial resources.
Ents are often described simply as walking trees, but Tolkien’s concept is more specific. They are sentient shepherds created to protect trees, while Entwives represent a related but separated tradition associated with gardens and agriculture.