For licencing purposes an umbraco project is the collection of Umbraco instances that make up the deployment of a specific site or suite of sites

So for example you might have multiple developers, pushing changes to a development site, which then goes to a stage or QA Site, once things are approved they go to a live site, and that site may well be load balanced.

All the Umbraco sites in this process would be considered part of the same project.

If you have multiple clients all with their own live sites, then that would be multiple projects, and you would need a licence for each one.

Lets not get bogged down with legal speak, here are our simple terms and conditions

• One licence gives you the right to use the software on any umbraco installation associated in the production of the website located at the specified domain
• A licence is non-transferable, and cannot be used for multiple clients or sites not considered to be part of a single deployment chain
• We own the code, and you can't modify it, steal it, crack it or try to pass it off as your own
• We reserve the right to revoke a licence if we think it has been misused, sold on, stolen etc
• We accept no responsibility for the any loss of data, content, setting or anything else bad through the use of this software