Deployment in the context of software development is the process by which an application or software update is delivered and made available to users. This involves transferring the software from a development environment to a production environment where it can be accessed by users. Deployment can include steps like installing and configuring software, setting up necessary databases, and ensuring that the system is secure and performs as expected. The deployment process can be manual or automated and is a critical phase in the software development lifecycle, marking the transition from development to actual use.