A voltage loss from differences between interfacial and bulk reactant or product activities caused by finite mass transport.

A voltage loss from ionic and electronic resistance, ideally $IR$.

Additional voltage needed to nucleate or grow a new phase, or overcome a phase-transformation barrier. It can cause an initial voltage dip and voltage hysteresis.

An activation-controlled large-overpotential relation $|\eta |=b{\log }_{10}(|j|/j_0)$. The Tafel slope $b$ uses volts per decade when the logarithm is base ten. Exchange current density and operating current density must use the same area convention.

The equal magnitudes of the opposing partial electrode-reaction current densities at equilibrium. Their net current is zero. The area convention, activities and temperature must be specified; an exchange current density alone does not specify a nonlinear current-potential curve.

A limiting rate of charge transfer per area imposed by reactant transport or another bottleneck. In a simple diffusion film, $j_L=nFD{c}_b/\delta$ and a consuming electrode has $c_s/c_b=1-j/j_L$. Increasing internal roughness does not necessarily increase external mass-transfer flux proportionately.

A kinetic model for the net electrode current near and away from equilibrium. For a single effective reaction with consistent activities and ${\alpha }_a+{\alpha }_c=1$, $j=j_0[\exp ({\alpha }_{a}nF\eta /RT)-\exp (-{\alpha }_{c}nF\eta /RT)]$. Near equilibrium it gives $j\simeq j_{0}nF\eta /(RT)$; at sufficiently large overpotential one exponential gives the Tafel equation. Multistep reactions can require a different kinetic interpretation.

Maintenance or assessment of multiple ecosystem functions together. Functions can depend on different traits or conflict, so performance in one process cannot stand in for every other process.

The amount of carbon held in a specified pool or system. It is a stock, distinct from gross uptake or its rate of net change; large old stocks can coexist with small current fluxes.

Carbon production remaining after subtracting autotrophic respiration from gross primary production. It need not remain stored, because consumers, decomposers and disturbance can return or export carbon.

The difference between gross primary production and both autotrophic and heterotrophic respiration. A full storage budget must additionally account for disturbance and lateral transfers.

Interchange of sulfur substituents through reactions such as thiolate attack on a disulfide. Rates and equilibria depend on protonation, solvent and redox conditions.

The ratio of a specified downward dry deposition flux to its reference near-surface concentration. It has units of speed but need not be an actual particle settling speed: transfer resistance and surface uptake can both control gas dry deposition.

A monotonic queue keeps candidate values in sorted order while a window moves through a sequence. For window maxima, discard smaller or equal values from the back before appending a new value, and remove expired indices from the front. The maximum is always at the front. Each index enters and leaves at most once, so all windows can be processed in linear time.

A frequency change associated with rotation and exchange of angular momentum. If an optical element rotates at angular velocity $\Omega$ about a chosen axis and gains angular momentum $\Delta L$ from a photon, its mechanical energy gain is $\Omega \Delta L$ in the prescribed slow-rotation model. Energy conservation then gives photon frequency change $\Delta \omega =-\Omega \Delta L/\hslash$. The rotating half-wave plate frequency shift is a spin-polarization example.

In a scalar effective-mass dielectric model, the donor radius is $a_B^{\ast }={ϵ}_r(m_e/m^{\ast })a_0$. The effective mass reduces the kinetic-energy scale and dielectric screening weakens attraction. The corresponding binding energy scales as $(m^{\ast }/m_e){ϵ}_r^{-2}$ times the vacuum hydrogen binding energy.