| Altari (all-TAR-ee) | the Makers of the Tanu, and the ancestors of the Riven |
| Alvalaithen (al-vuh-LAYTH-en) | Chloe’s Tan’ji, the dragonfly, the Earthwing; with it, she can become incorporeal |
| Auditor | a type of Riven; though not Tan’ji, they can imitate the powers of nearby instruments |
| breach | the gap in time across which the Fel’Daera sees into the future |
| cleave | to forcibly and permanently rip apart the bond between a Keeper and his or her Tan’ji |
| cloister | one of the small safe havens of the Wardens, usually a walled garden containing a leestone and a falkrete circle |
| daktan (dock-TAHN) | a piece broken off a Tan’ji, usually through deliberate sabotage |
| dispossessed | term for a Keeper who is permanently cut off from his or her instrument, usually by cleaving or being severed for too long |
| doba | small stone buildings in the Great Burrow; living quarters |
| dumin (DOO-min) | a spherical shield of force through which almost nothing can pass; a dumin is created by crushing a small glass ball called a dumindar |
| empath | a Keeper who can read the minds of nonhuman animals |
| falkrete | the strangely shaped stones found in cloisters; usually arranged in a circle, only a few of these stones possess the power they once did |
| Fel’Daera (fel-DARE-ah) | Horace’s Tan’ji, the Box of Promises; with it, he can see a short distance into the future |
| Find, the | the solitary period during which a new Keeper masters his or her instrument |
| Great Burrow | the uppermost chamber of the Warren |
| harp | an instrument used by Tuners; only Tuners can use a harp, but harps are not Tan’ji |
| jithandra (jih-THAHN-drah) | a small, personalized Tan’kindi used by the Wardens for illumination, identification, and entry into the Warren |
| Keeper | one who has bonded with an instrument, thus becoming Tan’ji |
| Kesh’kiri (kesh-KEER-ee) | the name the Riven use for themselves (see “Riven”) |
| Laithe of Teneves (TEN-eevs) | a mysterious Tanu, a spinning globe, in Mr. Meister’s possession |
| leestone | a Tan’kindi that provides some protection against the Riven |
| Loomdaughters | the first Tan’ji made with the Starlit Loom; there were nine in total |
| Maw | the great chasm at the back of the Great Burrow |
| Mazzoleni Academy | the boarding school beneath which the Warren lies |
| Medium, the | the energy that powers all Tanu |
| Mordin | Riven who are particularly skilled at hunting down Tan’ji |
| Mothergates | mysterious in nature, the three Mothergates are the structures through which the Medium flows before reaching out to power all Tanu in the world |
| Nevren | a field of influence that temporarily severs the bond between a Keeper and his Tan’ji; Nevrens protect the Wardens’ strongholds |
| oublimort | a Tanu within the Warren meant to confound unprepared visitors |
| oraculum | a Tan’ji belonging to Mr. Meister, a lens that allows him to see the Medium |
| passkey | a Tan’kindi that allows passage through certain walls |
| Perilous Stairs | the cliffside staircase that leads down into the Maw in the Warren |
| raven’s eye | a weak and portable kind of leestone, a Tan’kindi |
| Riven | the secretive race of beings who hunger to claim all the Tanu for their own; they call themselves the Kesh’kiri |
| San’ska (sahn-SKA) | the home cloister, the haven nearest to the Warren; its leestone is a magpie |
| sever | to temporarily cut a Keeper off from his or her Tan’ji |
| Staff of Obro | Gabriel’s Tan’ji, a wooden staff with a silver tip; it releases the humour, which blinds others but gives him an acute awareness of his surroundings |
| Starlit Loom | the very first Tanu; a Tan’ji that gives its Keeper the power to make new Tanu |
| Tanu (TAH-noo) | the universal term for all of the mysterious devices created by the Makers; the function of these instruments is all but unknown to most (two main kinds of Tanu are Tan’ji and Tan’kindi) |
| Tan’ji (tahn-JEE) | a special class of Tanu that will only work when bonded with a Keeper who has a specific talent; “Tan’ji” also describes the Keeper himself or herself, as well as the state of that bond—a kind of belonging or being |
| Tan’kindi (tahn-KIN-dee) | a simpler category of Tanu (raven’s eye, dumindar, etc.) that will work for anyone; unlike Tan’ji, Tan’kindi do not require a special talent or a bond |
| Tan’layn (tahn-LAIN) | the term for Tan’ji that do not currently have a Keeper; the unspoken |
| Tinker | a Kesh’kiri word for ordinary humans |
| tourminda (tour-MIN-dah) | a fairly common kind of Tan’ji that allows its Keeper to defy gravity; such Keepers—like Neptune—are called tourmindala |
| Tuner | though not Tan’ji, Tuners can use instruments called harps to cleanse and tune other Tanu |
| Tunraden (toon-RAH-den) | Brian’s Tan’ji, a Loomdaughter |
| Vithra’s Eye | the name of the Nevren that guards the Warren; very powerful |
| Vora | Mrs. Hapsteade’s Tan’ji, the quill and ink; it is used to determine the abilitites of potential new Keepers |
| Wardens | the secret group of Keepers devoted to protecting the Tanu from the Riven |
| Warren | the Wardens’ headquarters beneath the city, deep underground |