Glossary

ADS suits keep the occupant at one bar regardless of ambient pressure. Mobility is achieved through rotary joints at the shoulders, elbows, hips, and knees; the engineering art is maintaining rotation against crush loads. Physiological risk shifts entirely to mechanical failure — the diver breathes surface-mix air throughout.

Anchorages are distinguished from transient stations by structural commitment to substrate — driven piles, rock bolts, or weighted cradles. The term carries no operational implication; an anchorage may be staffed, automated, or decommissioned. Size ranges from single-lock shelter modules to city-scale complexes.

Modern oceanography treats the bathyal zone as the lower mesopelagic and the upper bathypelagic together; the archive uses the older convention that reserves the term for what the Pelagine seats actually inhabit. Crewed access at these depths is by submersible only; ADS suits do not extend reliably below seven hundred metres.

In post-migration usage the term has acquired institutional weight beyond its strict cartographic sense — bathymetric now reads as a claim of jurisdiction over a depth band, not merely a register of having mapped it. The Conservancy's name is the canonical example.

Standard equipment in the recreational and technical tiers (0–100 m). At saturation depth the question of buoyancy is decoupled from breathing-gas volume — divers leave the BCD on the platform and operate from the habitat directly, making the term effectively shallow-water vocabulary.

In day-to-day speech the Conservancy may refer to the institution, the saturation chamber the institution maintains at Varangurd, or — within a rotation — the particular liaison officer one happens to be working with. Usage rarely clarifies which.

DSVs maintain an internal atmosphere at or near one bar, placing depth limits on the hull and viewport rather than on the occupants' physiology. The category encompasses research submarines, survey craft, and the larger expedition-class vessels used for hadal work below 6 000 metres.

The office carries no exact human equivalent. Envoys operate within a mandate set by the Court and do not negotiate beyond its limits; they report contacts rather than conclude agreements. Their tenure is irregular and their recall seldom explained.

The Guild holds no territorial authority but commands practical leverage through protocol certification; a habitat whose surface link falls outside Guild-ratified standards loses access to the shared relay network. Helmsward Crossing's relay cluster is among the Guild's most trafficked installations outside Varangurd itself.

The term is from Hades, after the Greek underworld. Crewed visits to hadal depths are conducted by purpose-built full-ocean-depth DSVs and are rare enough that each is logged centrally; the Conservancy maintains the running register.

Below this band, ambient pressure exceeds the physiological tolerance window for saturation divers on standard heliox mixes without extraordinary intervention. The zone is also where Pelagine acoustic signatures first become consistently detectable on standard hydrophone arrays, a coincidence that has acquired cultural weight disproportionate to its technical significance.

Beyond the lower rib, depth and topographic complexity place transit outside routine saturation-diving range. The ridge itself is sporadically instrumented; its eastern face is among the less-documented formations adjacent to a major anchorage, a gap the Conservancy has flagged repeatedly.

Markers I through VIII sit at depth bands that human ADS work or saturation operations can comfortably reach; Marker IX is the deepest currently in active use. Each is co-administered by the Bathymetric Conservancy and a recognised Pelagine polity, and approach to any Marker requires the established two-stage hail.

Sited at three hundred and eighty metres, Marker IX is jointly administered by the Bathymetric Conservancy and the Tyrian Court, and hosts the quarterly liaison meetings between human and Pelagine signatories. Approach is by ADS suit on the human side; the two-day pre-conditioning and six-day decompression bracket each one-hour exchange.

In the working country this is the band between the deepest saturation habitats and the upper edge of submersible operations — visible from no anchorage, dark to the unaided eye, but still receiving enough downward light that surface-illuminated transits can read direction by it. Most of the day-to-day cable-tending in the archive happens above its lower boundary.

Real-world certification is preserved in the archive without modification: visitors arriving from the surface for shallow-shelf dives carry the same open-water credentials they would carry today, and the same agencies issue them. The realism is intentional — the diving is not the part of this world that is fictional.

What human observers have grouped under "Pelagine" may represent more than one lineage or affiliation. The name derives from pelagic, applied provisionally in early survey reports and subsequently formalised by the Conservancy. Pelagine sources have neither confirmed nor contested the term.

The working gloss — sustained presence over a span — is acknowledged by interpreters as inadequate. The concept appears in contexts that suggest it carries evaluative weight, but whether it denotes something like patience, endurance, or an entirely different category is not established. It is listed here because it recurs; it is not listed here because it is understood.

Material selection — high-strength steel, titanium, syntactic foam composites, or borosilicate glass for viewports — determines the rated crush depth. Hull integrity is the binding design constraint for all crewed deep operations; redundancy in fastener, seal, and viewport systems is mandatory by convention and by most colonial codes.

Contact protocols with the Pearled Council differ from those used with the Court; the Council appears to respond to harmonic acoustic signals where the Court uses broadband pulse sequences. Whether this reflects linguistic difference, cultural preference, or a deeper divergence in cognition is an open question in the survey literature.

Human observers access the spectrum instrumentally; raw sensor output is dense and partially interpretable at best. The spectrum's lower acoustic boundary has not been reliably established. What is legible to analysis appears to be a fraction of the total signal environment; the remainder is, by current understanding, unresolved noise or structure beyond present interpretive models.

Standard equipment for technical-tier work below thirty metres, where the gas economy of open-circuit becomes punitive. Rebreathers also permit the long, near-silent observation runs that the survey occasionally requires near Pelagine settlements; the absence of a bubble signature is a courtesy as much as a stealth feature.

Saturation allows divers to work from bell-based lock-out systems for extended shifts without accumulating repeated decompression obligations. The technique underpins most deep habitat construction; the Meridian Spine's pressurised work corridors were installed largely by saturation teams.

No single object constitutes a surface link; the term names a function, not a component. Redundancy is layered: hardline fibre where depth and geography permit, acoustic modems in the gaps, satellite relay where the water column is too turbulent for reliable acoustic paths. The Filament Guild maintains the agreed protocols spanning all three layers.

The practice predates its name: operators silenced non-essential systems and noted whatever the hydrophone array caught unaided. The journal entry — author uncertain, date placed in the early survey period — described the experience and the phrase spread. The practice is now semi-formalised on Conservancy survey descents, though its standing as protocol rather than custom remains debated.

The label is primarily used by undersea communities; Surfaceborne populations rarely apply it to themselves. Lipless Reach is the closest mapped zone to the surface-borne sphere of control, and traffic through it is monitored by both sides with varying degrees of formality.

Helium displaces nitrogen to mitigate narcosis; oxygen fraction is reduced as depth increases to stay within the partial-pressure window the lungs tolerate. The blend has a recognisable cold and weightless quality at the regulator — or, more often, no quality at all, which is the point.

The adjective precedes a wide range of nouns in survey literature — Tyrian architecture, Tyrian signalling, Tyrian-held zones — with varying precision. Used loosely, it covers anything provisionally attributed to Court influence. Used strictly, it designates formal Court affiliation as distinct from unaffiliated Pelagine activity.

The upper rib sits at saturation-diving depth along most of its length, making it the most heavily cabled and pipe-run formation in the basin. Survey teams use it as a navigational baseline; the ridge is lit at intervals by marker buoys whose intervals encode bearing information for inbound traffic.

Vent fields are transient on geological timescales; a field active for a century may go cold within decades, displacing the communities dependent on it. Around Black Lung and associated sites, vent chemistry is exceptionally sulphur-rich, producing conditions that favour specialist fauna found nowhere else in the survey region.