Current is a word with related meanings centered on movement or the present time. As a noun it most commonly denotes a flow—of electric charge, water, or air—moving steadily along a path. As an adjective it means existing or prevailing now (for example, "current events" or "current practice").
Main types
- Electric current: the rate of flow of electric charge, measured in amperes.
- Fluid current: steady movement of water in rivers, oceans, and canals.
- Atmospheric or air currents: persistent flows in the atmosphere such as jet streams or local breezes.
- Figurative/current as adjective: relating to the present time or recent developments.
In physics, electric current is a central concept in circuits and electronics. It may be direct (DC) or alternating (AC). Conventionally current direction is taken from positive to negative, a convention established before electrons were understood; electron flow is opposite to this conventional direction.
Oceanic and river currents transport heat, salt, nutrients and organisms, and they shape climate and navigation. These currents arise from wind forcing, differences in temperature and salinity, gravity, and the Coriolis effect on a rotating Earth. Atmospheric currents include large-scale patterns like trade winds and more localized flows such as sea breezes.
The word traces to Latin currere, to run, and entered English via Old French. Over time it broadened from literal flow to temporal senses—what is running now. In technical fields "current" can also have specialized meanings, for example in mathematics and geometric measure theory, where a "current" generalizes oriented surfaces for integration.
Practical concerns include measurement and safety: ammeters measure electric current; flowmeters and current meters measure water movement. Distinctions to note are between flow rate and velocity, between conventional and physical directions of charge, and between transient flows and stable currents that persist over time.