IDEF3 Standard

The vector stencils library "Terminals and connectors" contains 43 element symbols of terminals, connectors, plugs, polarized connectors, jacks, coaxial cables, and conductors.
Use it for drawing the wiring diagrams, electrical layouts, electronic schematics, and circuit diagrams.
"An electrical connector is an electro-mechanical device for joining electrical circuits as an interface using a mechanical assembly. Connectors consist of plugs (male-ended) and jacks (female-ended). The connection may be temporary, as for portable equipment, require a tool for assembly and removal, or serve as a permanent electrical joint between two wires or devices. An adapter can be used to effectively bring together dissimilar connectors.
There are hundreds of types of electrical connectors. Connectors may join two lengths of flexible copper wire or cable, or connect a wire or cable or optical interface to an electrical terminal.
In computing, an electrical connector can also be known as a physical interface... Cable glands, known as cable connectors in the US, connect wires to devices mechanically rather than electrically and are distinct from quick-disconnects performing the latter." [Electrical connector. Wikipedia]
"A terminal is the point at which a conductor from an electrical component, device or network comes to an end and provides a point of connection to external circuits. A terminal may simply be the end of a wire or it may be fitted with a connector or fastener. In network analysis, terminal means a point at which connections can be made to a network in theory and does not necessarily refer to any real physical object. In this context, especially in older documents, it is sometimes called a "pole".
The connection may be temporary, as seen in portable equipment, may require a tool for assembly and removal, or may be a permanent electrical joint between two wires or devices.
All electric cell have two terminals. The first is the positive terminal and the second is the negative terminal. The positive terminal looks like a metal cap and the negative terminal looks like a metal disc. The current flows from the positive terminal, and out through the negative terminal, replicative of current flow (positive (+) to negative (-) flow)." [Terminal (electronics). Wikipedia]
The shapes example "Design elements - Terminals and connectors" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the Electrical Engineering solution from the Engineering area of ConceptDraw Solution Park.