Generally, both "receptacle" and "container" refer to an object that contains some other object(s). What are the differences between these two words? Do they differ in meaning, usage, or origin?
Receptacle <-- receives something
Container <-- contains something
Sender <-- sends something
A receiver uses his receptacle to receive something. Then he puts it into his container (memory) to keep it contained and safe.
1375-1425; Middle English (< Old French) < Latin receptāculum reservoir, equivalent to receptā(re) to take again, receive back (frequentative of recipere to receive ) + -culum -cle2
An instructive synonym for receptacle in an electrical sense is socket (discussed in depth here under difference between “socket” and “outlet”). Socket can't usually be a synonym for container.
A major part of the difference in use is to do with the purpose. You can call a litter bin a trash container or a trash receptacle. In the former case you're emphasising storage, in the latter, you're emphasising acceptance.
You may have been a little unlucky with your choice of dictionary. Merriam-Webster has "one that receives and contains something", Cambridge has "a container used for storing or putting objects in" (emphasis mine in both cases).
A trash bin may be called a trash receptacle or a trash container, but a power receptacle would not be called a power container. The "receiving" done by a power receptacle, in my connotation is that it receives the plug from the device to be powered.
There is some overlap but, as others have mentioned, the root of "receptacle" is "receive" and the root of "container" is "contain".
You could look to the common phrase, "place the item in the proper receptacle", and derive that receptacle is a more specified type of container; a container designated to receive a particular item. Consider where trash is sorted by different materials; glass goes into the glass receptacle, paper in the paper receptacle, etc.
The difference is in what the object is used for. When I see "container" I think of something people put stuff into that the want to store for some indefinite period of time, then remove and use. When I see "receptacle" I think of something that people put stuff into for a specific reason, that someone else is going to remove to use for whatever purpose.
I put my leftover dinner in a plastic container so I can take it to work tomorrow.
I dropped the empty can in the aluminum receptacle.
"Receptacle" can also refer to where you plug electrical cords, but, in AE at least, it is more often called an "outlet".