Terms starting with O

Elastomer ring with a round cross-section that seals demountable vacuum joints by being squeezed into place.

The principal lunar diurnal constituent, period about 25.82 hours, created by the Moon's declination.

A control that measures flue gas oxygen and continuously adjusts the air-fuel ratio to hold it at target.

Optical brightening agent: a dye that absorbs UV light and re-emits it as blue, making paper look whiter.

A submerged object that hinders vessels or fishing and is not a wreck or natural rock, such as piles or debris.

Out-of-control action plan: the scripted checklist that tells operators exactly what to do when an SPC chart fires.

Optical Density: a logarithmic measure of how strongly a filter or laser eyewear blocks light at a given wavelength.

Structured CAD-to-fabrication data format that packs layers, drills, netlist and part data into one package.

One factor at a time: changing a single input while holding the rest fixed, the habit designed experiments replace. Shop talk

Describing a two-part adhesive dispensed with the wrong proportion of resin to hardener. Shop talk

Describes paper whose color has drifted outside the tolerance of its approved standard. Shop talk

Two equal bends in opposite directions that shift a conduit run sideways to clear an obstruction or enter a box.

A constant error that shifts every reading by the same amount, most often seen as a nonzero reading at zero input.

Crew and plant slang for liquid asphalt binder, as in oil content or a load that looks short on oil. Shop talk

Lab testing of in-service oil samples to judge oil condition, contamination and machine wear.

Slow spread of a thin oil film along metal surfaces, carrying pump fluid far from where it started.

Shop name for the tapered, pressurized film of oil that lifts a shaft off a sleeve bearing. Shop talk

Oxidative induction time: a measure of how much antioxidant protection remains in a polyolefin geosynthetic.

A veteran railroader with long seniority, respected for knowledge and sometimes resented for it. Shop talk

Box made to fit into an existing finished wall or ceiling through a cut hole, without access to the framing.

A forged branch fitting welded onto a run pipe to make an outlet without cutting in a tee.

On-load tap changer: a transformer switch that changes the turns ratio under load to regulate voltage.

Optical Loss Test Set: a light source and power meter used together to measure end-to-end link loss.

The OM1 to OM5 performance classes for multimode fiber, each rated for bandwidth and reach at a given data rate.

Derailed: off the rails with at least one wheel down on the ties or ballast. Shop talk

Conduit strap with a single screw hole, used to fasten a conduit run to a wall or structure.

A loss-test reference set with a single launch jumper between source and meter, so both link end connectors are counted.

On a planned survey line and logging data; going offline means ending the line and closing the file. Shop talk

Survey slang for paired on and instant-off potential readings taken while rectifiers are being interrupted. Shop talk

Out of control: shorthand for a point or chart that has violated a control limit or run rule. Shop talk

Out of specification: a measured result outside the spec limits, meaning the product itself is nonconforming.

Out of tolerance, an as-found calibration result outside the instrument's allowed limits. Shop talk

A sheet's ability to hide what lies behind it, expressed as a percentage from readings over black and white backings.

The longest gap allowed between applying adhesive and closing the joint while it can still wet the second part.

Widening a specification limit so more product passes, instead of fixing the process that makes it. Shop talk

Graph of a sampling plan's probability of accepting a lot against the lot's true defect rate.

The automatic-reset control that cycles or modulates the burner to keep steam pressure or water temperature in range.

Optical Parametric Oscillator: a tunable source that splits pump photons into two longer-wavelength beams in a nonlinear crystal.

A one-way valve for light that passes a beam forward and blocks reflections from returning to the laser.

A dimpled surface texture like the skin of an orange, the most common appearance complaint on powder.

A survey order for coastal waters and fairways where features matter but under-keel clearance is less critical.

A radioactive source that has escaped regulatory control because it was lost, stolen, abandoned or never licensed.

On sheet: a report of the time a train passed a station, or the act of reporting it. Shop talk

Outside screw and yoke: a rising-stem valve design with its stem threads above the packing, out of the fluid.

Optical Singlemode 2: the low-water-peak cabled singlemode grade used for most indoor and outdoor singlemode installs.

Optical Time Domain Reflectometer: a tester that maps a fiber's loss and events by timing light reflected back along it.

Past its calibration due date, so the instrument is not approved for use regardless of how well it performs. Shop talk

Shop phrase for welding in any position other than flat, especially vertical and overhead. Shop talk

A control strategy that lowers hot water supply temperature as outdoor temperature rises, following a set curve.

Gas escaping from a porous substrate during cure and blowing pinholes, bubbles or craters through the film.

Slow release of gas from the surfaces and bulk of materials inside a vacuum system.

Gas escaping into curing sealant or membrane from punctured rod or damp concrete, leaving bubbles and pinholes.

Observation that sits far from the pattern of the rest of the data, either a genuine extreme or an error.

The partially transmitting resonator mirror through which the laser beam leaves the cavity.

Out-of-round flexing of a rotary kiln shell under its tires, which crushes and loosens the brick lining.

The temperature-controlled mount that holds a nonlinear crystal at its phase-matching temperature. Shop talk

A temperature recording from thermocouples on real parts as they travel through the cure oven.

Cure that went too hot or too long, causing yellowing, gloss loss and brittle film.

Pumping more grease into a bearing than it needs, causing churning, heat and blown seals.

Width by which neighboring rolls of geotextile, geogrid or GCL lie over one another to keep a continuous layer.

The share of each swath that is also covered by the neighbouring line, planned in to guard against gaps.

So much cathodic current that potentials get too negative, risking coating damage and hydrogen problems.

Spray material that misses the part or fails to stick, ending up in the collector or on nearby surfaces.

Tapping a nut oversize after galvanizing so it will fit over the thick zinc on a hot-dip galvanized bolt.

A higher-frequency constituent, such as M4, generated when a tide distorts in shallow water.

Class from I to IV ranking equipment by its position in an installation and the surges it must survive.

Thin oxide films formed on metal particles in flight, showing as dark stringers between splats.

Cutting steel by heating it to ignition with a flame, then burning it away with a jet of oxygen.

Air at the surface blocking the cure of free-radical adhesives, leaving them sticky where exposed.

Deep localized corrosion pits in boiler steel caused by dissolved oxygen in the water.

A chemical fed to boiler feedwater that reacts with and removes the last traces of dissolved oxygen.

Chemical that strips dissolved oxygen from water to stop oxygen pitting in boilers and injection systems.