In CIC, a Message can mean different things depending on what type of Integration you are building and what industry you are in. If you are building a B2B integration where your partner is sending EDI files containing messages, a message can represent a Purchase Order (850) or an Invoice (810) for retail and manufacturing industries or a Load Tender (204) and Motor Carrier Freight Details and Invoice (210) for the Logistics industry. Similarly, if you are building an integration to an application like Amazon Marketplace, a message can represent a Purchase Order from Amazon or an Order Status Update to Amazon. There are other cases, where you may be building an integration between two applications, and in that case, a Message might represent a single update in one application that is being synchronized with the other application.
In the case of EDI, there is a standard definition of what constitutes a message within an EDI File, namely all content between the ST and SE segments. For non-EDI cases, it is up to the integration designer to define a message.
The example above shows an example of a message as it is displayed in the Messages screen in tile view mode. A message has a type, for instance, a Purchase Order or an Invoice. The message type is shown as well as an icon representing the message type. Each message will have a ID that uniquely identifies that particular message, for example, Order 1537801284120. If the message was sent to or from a Partner, the Partner name and Partner ID are indicated. The message description is a brief summary of the most pertinent attributes of a message. For instance, in the example of an Order, it might show the number of items in the order and the total amount. Each message type has its own message description that makes sense for that message type. The message description along with the message type icon and message type name can all be customized to your liking. The date and time that the message was sent is also shown. Lastly, if functional acknowledgements are set up for your integration, the Functional Acknowledgement status is displayed on the bottom right of the tile. For more details, see Working with Messages.
Messages represent an important part of operating your system as Messages are the smallest unit of transactional data you can use to observe activity on CIC. Messages are shown in the Activity > Messages page as well as on the Job Detail screen for the particular Job that processed a given message.