This was a question raised by one of the software engineers in my organisation. I\'m interested in the broadest definition.
Generally, you will get a lot of theoretical but one of the easiest ways to differentiate these two concepts is as follows:
In order to get a service, you need a service number. This service number is called a port. Simple as that.
For example, the HTTP as a service is running on port 80.
Now, many people can request the service and a connection from client-server has established. There will be a lot of connections. Each connection represent a client. In order to maintain each connection, the server creates a socket per connection to maintain its client.