CAL - A software license that allows a client computer to connect to server software. CALs, in general, are available as User, Device or Concurrent versions. 

• A User CAL allows one user to connect to the server software.
• A Device CAL allows one client device to connect to the server software.
• A Concurrent CAL allows a unique client connection at any point in time. For example, if an organisation has 20 employees but only 10 of them are ever working on the organisation’s network at any one time, then 10 Concurrent CALs are needed

Compliance - This term describes the use of purchased software products in keeping with software publishers' end-user license agreements.

Downgrade Right - Authorizes you to use the prior versions of the specific software – beside or instead of your current version, in accordance to your agreement terms and conditions. Downgrade rights may be specific to a product or generalized for all products of a vendor.

EULA - End User License Agreement. Contract between the licensor and purchaser of a software product, establishing the purchaser’s right to use the software.

Floating Licence - Floating licenses are pooled licenses that can be shared across a group of users.  Allows installation on multiple machines but limits the number of active sessions.  Also know as a concurrent licence.

Freeware - Proprietary software authorized to use without purchase, though typically still requiring licenses and subject to copyright law.

FTE - Full Time Employee. A unit of measure which indicates the workload of an employed person.

LAN - This stands for local area network and is a computer network that interconnects computers in a limited area such as a home or office building

Licence - Provides the legal right to install, use, access, display, run, or otherwise interact with a software program bought, not necessarily including the direct rights to additional media, manuals, or even support.

License Key / Serial Number - Software-based key or number which certifies that the copy of the software is original. License keys are often used for activation of the software.

Maintenance & Support -  is often sold on a subscription basis alongside software licensing. It provides the end user with updates, patches and version upgrades as well as access to technical support resources normally provided by the manufacturer. 

Open Source Software (OSS) - Software with publicly available source code. Open source software does not mean that the software is free or not to be licensed in general, but the open source license grants the right to consult, change/improve and redistribute the source code to licensees. Open source is often used as a marketing term in order to distribute software with commercial editions and free (restricted) editions by vendors.

Operating System Environment (OSE) - An operating system instance, or a virtual operating system instance, which enables separate machine identity.

Original Equipment Manufacturer (OEM) - A license program for computer manufacturers to provide their hardware with licensed software, especially operating systems.

Perpetual - A license that has been paid for once and does not require renewal, providing the rights to use the software for as long as required.

Processor (Processor Core, Central Processing Unit (CPU)) - Core of a computer (client or server) that receives and acts upon all instructions – handling calculations and control operations. Devices (usually servers) are often licensable per-processor or per-processor core.

Physical Core - Each physical processor contains smaller processing units called physical cores. Processors may be mono-core (single core), dual-core (2 cores), quad-core (4), hexa-core (6), etc.

Reseller - Company (or person) authorized by a vendor to purchase and resell software. Resellers are important in licensing as they keep records of customers’ purchases.

Server  - Physical computer comprised of processing units, memory, and input/output capabilities that executes requested procedures, commands, or applications for one or more users or client devices. Server is a unit of measure by which the program can be licensed.

Shareware - Category of software products free for download for trial purposes in the first place, allowing potential customers typically purchasing a license after trial.

Software  - Software is an intellectual property. Most often, it is licensed by means of a licensing agreement with third-party vendors. With the license (agreement) come rights – such as the right to use the software under certain licensing restrictions, and duties – such as license and maintenance costs. These rights and duties are detailed in the licensing documentation of each specific software product, and vary according to product, edition and version, sometimes also by language, geography, etc. In fact, it can be hard to even identify the correct documentation (challenge #1) in the first place. The licensing documentation contains two crucial topics: the license metrics and their associated restrictions (challenge #2), which can often be difficult to interpret and to abide by.

Software as a Service (SaaS) - On-demand services as application service providing. Nearly all vendors provide SaaS, however under different names.

Software Assurance (SA) - Maintenance program offered by Microsoft which provides the end user with a range of benefits including the rights to upgrade to the latest version of the software that they have SA against.  See also Maintenance & Support.

Software Asset Management (SAM) - A process of recording and maintaining software licenses across an organization. 

Subscription - A subscription provides time limited (often annual) access to a service or product.

Vendor - A commercial organization that acquires or develops software to sell to the end user.

WAN - A computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs).  The largest WAN in existence is the Internet!

Workstation (Client Device, Client Computer, Client) - Device (computer) intended for use as a client. Workstations are important in licensing as they are attached to specific licensing requirements, for instance in user metrics (the user of the device) or device metrics

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