Anode: Electrode where oxidation occurs; in galvanic cells = negative terminal; in electrolytic cells = positive terminal.

Cathode: Electrode where reduction occurs; in galvanic cells = positive terminal; in electrolytic cells = negative terminal.

Cell constant: Ratio l/A (length between electrodes / cross-sectional area); units $cm^{-1}$. Determines how specific conductance relates to measured conductance: κ = G × (l/A).

Concentration cell: An electrochemical cell with identical electrodes but different ion concentrations. E°cell = 0; EMF arises purely from concentration difference.

Conductance (G): Reciprocal of resistance (G = 1/R); unit = Siemens (S) or mho ($\Omega$^{-1}).

Degree of dissociation (α): Fraction of electrolyte that dissociates into ions; α = Λm/Λ°m for weak electrolytes.

Electrochemical equivalent (Z): Mass deposited per coulomb of charge; Z = M/(nF) in g/C.

Electrochemical series: Arrangement of electrode systems in order of their standard reduction potentials.

Electrode potential: Potential difference between electrode and its surrounding solution; measured against SHE.

Electrolytic cell: Non-spontaneous cell requiring external electrical energy to drive a chemical reaction.

Faraday (F): 96485 C ≈ 96500 C; charge carried by 1 mole of electrons.

Fuel cell: Electrochemical cell that converts chemical energy of a continuously fed fuel ($H_{2}$, $CH_{4}$) directly to electrical energy.

Galvanic (voltaic) cell: Spontaneous electrochemical cell that converts chemical energy to electrical energy.

Kohlrausch's law: At infinite dilution, limiting molar conductivity = sum of individual limiting ionic conductivities × stoichiometric numbers.

Limiting molar conductivity (Λ°m): Molar conductivity at infinite dilution (C → 0); maximum conductivity per mole.

Molar conductivity (Λm): Conductance of a solution containing 1 mol of electrolyte placed between electrodes 1 cm apart; Λm = κ × 1000/M.

Nernst equation: Mathematical expression relating cell EMF to standard EMF and reaction quotient: E = E° − (RT/nF) ln Q.

Oxidation: Loss of electrons; increase in oxidation number.

Oxidation number: Formal charge assigned to an atom in a compound based on electronegativity rules.

Reduction: Gain of electrons; decrease in oxidation number.

Salt bridge: KCl in agar gel connecting two half-cells; maintains electrical neutrality without mixing solutions.

Specific conductance (κ): Conductance of a solution with unit dimensions (1 cm between electrodes, 1 $cm^{2}$ cross-section); κ = 1/ρ; unit S/cm.

Standard electrode potential (E°): Electrode potential measured under standard conditions (1 M, 25°C, 1 atm) relative to SHE.

Standard hydrogen electrode (SHE): Reference electrode with E° = 0.00 V; Pt electrode in 1 M $H^{+}$ solution with $H_{2}$ at 1 atm.