What does capacitance mean?
Capacitance is a fundamental property in physics and electrical engineering describing how much electric charge a component or system can store for a given voltage. It arises whenever conductors are separated by an insulating material — a dielectric — as in a capacitor, the purpose-built component designed around this effect. Measured in farads (typically microfarads or picofarads in practice), capacitance determines how circuits respond to changing signals, filters noise, and stores energy briefly. The term appears constantly in electronics design, where engineers must manage both deliberate capacitance and unwanted 'stray' or 'parasitic' capacitance between nearby conductors. Beyond hardware, capacitance underpins everyday technologies such as touchscreens, which detect fingers by sensing tiny local changes in the field. Precise and technical in register, the word carries no emotional connotation but signals scientific rigour wherever it appears.
nounThe ability of a component or circuit to store electrical charge, measured as the ratio of stored charge to the potential difference across it; also, the measure of that ability itself.
- In physics and electronics: the property of a conductor or system of conductors by which it stores electric charge per unit of potential difference; the quantitative measure of this property, expressed in farads.
- More broadly: the ability of any device or arrangement to hold or accumulate an electric charge.
"Adding a larger capacitor increased the circuit's capacitance, allowing it to hold more charge between pulses."
"The engineer chose a dielectric material with a high permittivity to maximise the capacitance of the chip."
"Stray capacitance between adjacent traces can degrade signal integrity at very high frequencies."
Rarely pluralised; the mass-noun sense predominates. A plural appears mainly when comparing several distinct measured values or components.
"The two capacitors have different capacitances despite sharing the same physical footprint."
Your smartphone screen knows where your finger is because your body slightly changes the capacitance of the glass beneath it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of capacitance
Capacitance derives from the Latin 'capacitas' ('capacity', from 'capax', meaning 'able to hold much'), itself rooted in 'capere', 'to take or seize'. The English word emerged in the nineteenth century as physicists formalised the study of electricity, applying an existing Latinate noun of quantity to this new measurable property. It shares its root with words such as 'capacity', 'capacious', and 'capacitor', the latter coined alongside it for the charge-storing device. Related Latin descendants include 'captive' and 'receive', all tracing back to the sense of taking or holding.
Related word forms
How capacitance is actually used
A formal, technical term used almost exclusively in physics, electronics, and engineering contexts. It is uncountable in most usage, though specific values are given as 'a capacitance of ten microfarads'. The SI unit is the farad, named after Michael Faraday.
Easily confused with capacitance
Capacity refers generally to the amount something can contain or the maximum output of a system, while capacitance specifically denotes the electrical property of storing charge in a component or circuit.