In The Changing Light at Sandover (1982), James Merrill sketches a tableau of his study, singling out his hardbound set of the Oxford English Dictionary. Indeed, dictionaries were never far from his desk, and their presence is felt in much of his poetry, from interpolated definitions to pastiche etymologies and puns whose effectiveness depends upon a deep and lasting knowledge of the OED and American Heritage Dictionary. This essay takes as its starting point Merrill’s belief that dictionaries constitute a ‘collective unconscious’, discussing how the spirits of the dead are invoked not just by way of Merrill’s poetic experiments with Ouija boards, but through his ongoing fascination with the buried histories of words themselves. In close readings of Sandover, as well as some of Merrill’s later lyrics, it charts the poet’s lifelong preoccupation with acts of definition, and suggests that his poetry ultimately takes more delight in the ramifications of words than their roots.