In Infinite Jest, Wallace uses the word "annular" frequently, fitting it into a variety of seemingly unrelated contexts. It creates an interesting thread to follow through the disjointed narrative. According to the Oxford English Dictionary, annular means, "of or pertaining to a ring or rings, ring-formed, ringed."
Time takes an annular form in Infinite Jest. For one, the book starts in the final year of narrative time (Year of Glad), and then moves back via Hal's memory to a much earlier date. While this shift could be seen as a mere flashback, a jump back in a linear time scheme, it makes more sense when viewed as an annular move- the narrative comprises a giant ring, and DFW shifts back and forth along it, with equal ease in each direction.
To bring those two ends together in true annular form, at WYYY, there is "a numberless disk someone hung for a joke, to designate the annularized Great Concavity's No-Time" (183). The numberless disk is a "joke" in the same way Wallace's numberless disk section breaks are a "joke," pointing to the novel's annularized, narrative No-Time.
The O.E.D. also lists: "annular process or protuberance (in the brain): the Pons Varolii; ‘a process of the medulla oblongata; thus called by Dr. Willis  in regard it surrounds the same, much like a ring.’ Chambers Cycl. 1727-51." This annular process is uncannily similar to "the coaxial medulla" that the WYYY engineer pumps the music through "into the crawlspaces above the high false ceiling of the corpus callosum's idle tennis courts" (183). Here, Wallace turns architecture into a (prosthetic) body part, much like the phone center with a human temperature and the Antichrist's lymph node in The Broom of the System, only this time, with a radio instead of telephones.
Furthermore, the engineer who pumps the sound out through the annular coaxial medulla is also an annular physicist: his "graduate research specialty is the carbonated translithium particles created and destroyed billions of times a second in the core of a cold-fusion ring" (185). In this "cold-fusion ring" (a very annular set up indeed) the particles are created and destroyed in annularized No-Time, existing "mostly to explain gaps and incongruities in annulation equations" (185). These particles seem to me to correspond to the work we're supposed to do as readers. Ideally, one's neurons should be firing billions of times a second as one reads Infinite Jest, and this mass of thoughts serves to fill the gaps in the novel, gaps left by Wallace's use of annularized No-Time.
Later, as Joelle prepares to commit suicide, the ring of creation/destruction gets expanded to human level: "The ultimate annular fusion: that of an exhibit and its cage" (222).
Furthermore, extra-lingual aspects of Infinite Jest are annular. For example, the circular symbols in between paragraphs are certainly ring-shaped. On another level, they separate the different narrative threads, such that each thread becomes its own ring, in addition to forming a larger ring of the novel itself; this ring-within-a-ring structure comprises the novel's fractal-like structure.
The novel itself is annular: Intentional Fallacy notwithstanding, in an interview with Wallace said: "I mean this is probably a little pretentious to write a book this long and have it be designed to be read more than once." The book demands multiple readings precisely because its ending draws your right back to the beginning which is chronologically after the abrupt, unsatisfying "end."
James Incandenza creates a number of films about annular fusion:
- "Annular Fusion Is Our Friend": a "non-technical explanation of the processes of DT-cycle lithiumized annular fusion and its applications in domestic energy production:
- "Annular Amplified Light: Some Reflections": - "Second infomercial for Sunstrand Co., a non-technical explanation of the applications of cooled-photon lasers in DT-cycle lithiumized annular fusion."
- The Machine In The Ghost: Annular Holography For Fun And Prophet": Nontechnical introduction to theories of annular enhancement and zone-plating and their applications in high-resolution laser holography.
- "Valuable Coupon Has Been Removed": "a boy helps his alcoholic-delusional father and disassociated mother dismantle their bed to search for rodents, and later he intuits the future feasibility of D.T.-cycle lithiumized annular fusion."