The top level under your storage account to hold many blobs and metadata, more here.
Deployment
You submit a packaged code binary with configuration to Windows Azure, then a bunch of Windows Virtual Machines will be spin up and have your code inside, and code entry point will be called. When you no longer need it, you can delete the deployment.
Instance
One of your Virtual machines in your deployment, running Windows Server 2012 64 bit or lower.
Web Role
Within a Windows Azure Cloud Service Deployment, the instances that will run a web server to serve web pages.
Worker Role
Within a Windows Azure Cloud Service Deployment, the instances that will run code but without a 'face'.
xdrive
Windows Azure storage allows you to 'mount' a 'blob' as a local drive, e.g. 'f:\'. We use xdrive to hold program .exe files and common data files.
Fourtytwo related:
Reserved Variable Names
Currently only <xdrive> and <n>
Thread
You need to understand your program well, if it can be run in multithread model, then tell Fourtytwo by specify the Thread value; if it is a single thread program, Fourtytwo can't change that into a multithread program, but Fourtytwo will spin up multiple 'copy' of this program to use all CPU cores. e.g. if using Large instance (4 cores), when Thread value is 4, Fourtytwo will spin 1 copy; if the value is 2, Fourtytwo will spin 2 copies; if the value is 1, it will be 4 copies. So you might see it's possible for an instance to run different programs at the same time, then you need to understand how that will effect the performance due to the characteristic of each program on Memory, I/O, etc.