Here are several terms we use a lot in our line of work.

As so many of them get different definitions applied to them, depending on who is using them, we find it useful to share the definitions to which we subscribe. If you don’t see a term you expected to see, or if you want to engage in a discussion about ones you do see, don’t hesitate to let us know.

An action is an automated activity that is part of a stage in a deployment pipeline. An action executes a series of automated steps. Each of these steps must succeed in order for the action to succeed. If any of them fail, the actions stops and the stage fails. There may be 1-n automated actions within a stage.
Source: Stelligent
Continuous Delivery (CD)
Continuous Delivery is a software development discipline where you build software in such a way that the software can be released to production at any time.
Source: Martin Fowler
Continuous Integration (CI)
Continuous Integration (CI) is a development practice that requires developers to integrate code into a shared repository several times a day. Each check-in is then verified by an automated build, allowing teams to detect problems early.
Source: ThoughtWorks
Continuous Deployment
Continuous deployment is the next step of continuous delivery: Every change that passes the automated tests is deployed to production automatically. More explicitly, revisions are deployed to a production environment automatically without explicit approval from any human authority, making the entire software release process automated.
Sources: Puppet Labs (Carl Caum), and Amazon Web Services
Continuous Security
Continuous Security is the addressing of security concerns and testing in the Continuous Delivery pipeline.
Source: Stelligent
Cycle Time
Cycle time is the total time from the beginning to the end of your process, as defined by you and your customer. Cycle time includes process time, during which a unit is acted upon to bring it closer to an output, and delay time, during which a unit of work is spent waiting to take the next action.
Source: Six Sigma
Deployment Pipeline
A deployment pipeline is a way of orchestrating your build through a series of quality gates, with automated or manual approval processes at each stage, culminating with deployment into production.
Aliases: CD Pipeline, delivery pipeline, deployment production line
Source: Jenkins – The Definitive Guide
DevOps is the combination of cultural philosophies, practices, and tools that increases an organization’s ability to deliver applications and services at high velocity: evolving and improving products at a faster pace than organizations using traditional software development and infrastructure management processes. This speed enables organizations to better serve their customers and compete more effectively in the market.
Source: Amazon Web Services
The collection of resources that have been provisioned and configured. An environment is a provisioned and configured instantiation of multiple infrastructure resources that contain state.
Source: Stelligent
Disposable Environments
A pattern in which practitioners terminate environments when they are no longer in use versus making incremental changes to existing environments. When changes to environments are only made through automation (see Immutable Infrastructure), the default behavior is to dispose of all environment resources rather than making a incremental change to an existing environment. This approach ensures that all changes are applied in a controlled manner in order to reduce assumptions in where errors are introduced.
Source: Stelligent
Genba Walk
A Genba Walk denotes the action of going to see the actual process, understand the work, ask questions, and learn. It is known as one fundamental part of Lean management philosophy. Alias: Gemba Walk
Source: Wikipedia
Immutable Infrastructure (Environment)
Immutable Infrastructure is when you deploy new infrastructure when making changes instead of making changes to an existing environment. Most teams apply this pattern by only making these infrastructure changes through versioned automation. There are no manual changes made to environments. Furthermore, the infrastructure is always brought up in its entirety.
Source: Stelligent
In the cloud
A part of a phrase to be used when describing a service, application, or other things that are hosted or resident on a cloud provider such as AWS. Contrast this with the often used “on the cloud” … we have established that IN is preferred over ON in this case.
Source: Uncredited
The infrastructure refers to the generic components used to compose environments. While environments have state, infrastructure does not. Infrastructure includes everything that is not the application/service or the configuration of the infrastructure. It includes the operating system, application, web, database servers, etc. 
Source: Stelligent
Kaizen (改善?), Japanese for “good change”. It has been applied in healthcare, psychotherapy, life-coaching, government, banking, and other industries. When used in the business sense and applied to the workplace, kaizen refers to activities that continually improve all functions, and involves all employees from the CEO to the assembly line workers. It also applies to processes, such as purchasing and logistics, that cross organizational boundaries into the supply chain. By improving standardized activities and processes, kaizen aims to eliminate waste (see lean manufacturing). Kaizen was first implemented in several Japanese businesses after the Second World War, influenced in part by American business and quality management teachers who visited the country. It has since spread throughout the world and is now being implemented in environments outside of business and productivity.
Source: Wikipedia
Lead Time
Lead time is the latency (delay) between the initiation and execution of a process. For example, the lead time between the placement of an order and delivery of a new car from a manufacturer may be anywhere from 2 weeks to 6 months. In industry, lead time reduction is an important part of lean manufacturing.
Source: Wikipedia
Poka-yoke (ポカヨケ?) [poka yoke] is a Japanese term that means “mistake-proofing”. A poka-yoke is any mechanism in a lean manufacturing process that helps an equipment operator avoid (yokeru) mistakes (poka). Its purpose is to eliminate product defects by preventing, correcting, or drawing attention to human errors as they occur. The concept was formalized, and the term adopted, by Shigeo Shingo as part of the Toyota Production System. It was originally described as baka-yoke, but as this means “fool-proofing” (or “idiot-proofing”) the name was changed to the milder poka-yoke.
Source: Wikipedia
Queue Time
The time between sub-processes that the thing gets shuffled around or sits around waiting for someone to work on it.
Aliases: Also known as “Waiting & Transportation Time” or “Inventory/Transportation Time”
Source: Lean Glossary
Serverless Delivery
Solutions that embody the same fundamental tenets of continuous delivery while utilizing tools and techniques that complement the serverless architecture in Amazon Web Services (AWS).
Source: Stelligent (Casey Lee)
In the context of a deployment pipeline, a stage is a series of automated actions that provide coarse-grained feedback. At Stelligent, we name each of these stages based on the overall purpose. There may be 1-n automated stages within a deployment pipeline. The last stage will release the software to production environments. Often, this can result in a software system that gets to the production stage several times per day enabling the business to choose to deploy the good changes.
Source: Stelligent
Value Stream Mapping
Value stream mapping is a lean-management method for analyzing the current state and designing a future state for the series of events that take a product or service from its beginning through to the customer. At Toyota, it is known as “material and information flow mapping.” It can be applied to nearly any value chain.
Source: Wikipedia
Wait Time
Waiting is one of the 7 Wastes that most people recognize easily. Eliminating time spent waiting has been a focus of manufacturing improvement activities since the industrial age started. The motivation to eliminate wait time has been the driving force behind many of the other wastes. For example, to eliminate any chance of an employee waiting, large queues of work-in-progress (WIP) would be accumulated throughout the production process. Reducing wait time is an essential objective and important component of lean, but it is just one of the seven wastes. When people think of wait time, most picture a worker in front of a machine waiting for material to arrive or for the machine to cycle. This is one of the common types of wait time, but there are more subtle instances that are every bit as costly. Wait times are a major challenge in supply chain operations, as companies must wait days or weeks to replenish raw materials. Wait times also occur in many administrative functions, including the delays in the flow of information or approvals from one department to another, or the delay of waiting for an open position to be filled.
Source: Lean Genie