EV charging brings together telecom-style protocols, payments terminology and utility-industry jargon, often in the same sentence. This is a working reference to the terms that come up most often when evaluating a charging platform or reading about the industry - grouped by topic, not strictly alphabetical, with links to deeper coverage where it exists.
Protocols & standards
| Term | What it means |
|---|---|
| CSMS | Charging Station Management System - the backend software that talks to chargers, manages sessions and tariffs, and gives operators visibility into the network. See What Is a CSMS? |
| OCPP | Open Charge Point Protocol - the standard that lets a CSMS communicate with chargers from different manufacturers using the same message set. See What Is OCPP? |
| OCPI | Open Charge Point Interface - the standard that lets separate charging networks share charger availability and let each other's drivers roam and pay across networks. See What Is OCPI? |
| CPO | Charge Point Operator - the business that owns and operates the charging hardware and the account behind it. |
| eMSP | e-Mobility Service Provider - the business that holds the driver relationship (app, account, billing), which may or may not be the same company as the CPO that owns the hardware. |
| EVSE | Electric Vehicle Supply Equipment - the formal industry term for the physical charging unit. In everyday conversation people usually just say “charger.” |
| ISO 15118 / Plug & Charge | A standard that lets a vehicle and charger authenticate and start a session automatically over the charging cable itself, without a card, app or QR code. An emerging capability across the industry, not yet universal across hardware or CSMS vendors. |
Hardware & connectors
| Term | What it means |
|---|---|
| Connector | The specific plug/port a vehicle charges from - a single charging station usually has one or more connectors, each tracked and billed independently. |
| AC vs. DC charging | AC (“Level 1/2”) chargers rely on the vehicle's onboard charger to convert power, and are slower. DC fast chargers (“Level 3”/DCFC) convert power before it reaches the vehicle, charging much faster at higher hardware cost. |
| kW vs. kWh | kW (kilowatt) measures charging power - how fast energy is delivered. kWh (kilowatt-hour) measures energy delivered over time - what a driver is actually billed for under per-kWh pricing. |
| Firmware | The software running on the charger itself, distinct from the CSMS. Firmware updates are typically pushed remotely and are the usual path to adding OCPP feature support to existing hardware. |
Network operations
| Term | What it means |
|---|---|
| Uptime / availability | The share of time a charger is able to deliver a session on request. A blunt, easy-to-misread metric on its own - see Charger Uptime and Reliability. |
| Utilization | The share of available charging time actually used by paying sessions - the single biggest driver of connector revenue. See The CPO Business Case. |
| Fault / alert | A charger-reported error condition surfaced to operations - the trigger for a maintenance ticket, remote fix attempt, or technician dispatch. |
| Remote diagnostics | Investigating and resolving a charger issue from the CSMS console - reset, unlock, configuration check - without sending a technician onsite. |
| Site host | The property owner hosting chargers, distinct from the CPO operating them - often compensated through a revenue share. See The Site-Host Business Case. |
Commerce & billing
| Term | What it means |
|---|---|
| Tariff | The pricing rule applied to a session - per-kWh, per-minute, flat fee, or a tiered/time-of-day structure - configurable per station, connector or customer segment. |
| Idle fee | A charge applied after a session ends but the vehicle stays parked in the bay, meant to free up the connector faster for the next driver. |
| Revenue share | The split of session revenue between the CPO and the site host, typically negotiated as part of the hosting agreement. |
| RFID | A physical card or fob a driver taps to authenticate and start a session - an alternative to the mobile app, common for fleet and corporate access. |
| Corporate account | A billing arrangement where sessions are charged to a company account rather than an individual driver - the basis for fleet and employee-benefit charging programs. |
Business models
| Term | What it means |
|---|---|
| White-label | A platform that runs entirely under the operator's own brand - driver app, operator console and all - rather than the software vendor's. See White-Label vs. Single-Brand CSMS. |
| Multi-tenant | An architecture where one platform deployment serves multiple isolated brands, properties or reseller accounts. See What Is a Multi-Tenant CSMS? |
| Deployment model | Who hosts the CSMS - a managed cloud run by the vendor, the operator's own cloud account, or on-premise infrastructure. See Managed Cloud vs. Your Cloud vs. On-Premise. |
| Roaming | The ability for a driver on one charging network to authenticate, charge and get billed correctly on a partner network, coordinated via OCPI. |
For terms specific to the raw protocol traffic between a charger and a CSMS - BootNotification, Authorize, MeterValues and the rest - see the dedicated OCPP messages glossary.
Frequently asked questions
What's the difference between a CPO and an eMSP?
A CPO owns and operates the physical chargers. An eMSP owns the driver relationship - the app, account and billing. Many businesses are both at once; roaming (OCPI) exists specifically to let a driver from one eMSP charge on a different CPO's network.
Is “charging station” the same as “connector”?
Not quite - a charging station is the physical unit, which often has more than one connector. A dual-port station, for example, is one station with two connectors, each capable of running an independent session and each billed separately.
Does “white-label” mean the same thing as “multi-tenant”?
No, though they're often discussed together. White-label is about whose brand a driver sees. Multi-tenant is about whether the underlying platform can run several of those brands, or several separately-billed accounts, on shared infrastructure at once.