LMS
A learning management system is the software an institution uses to hold its courses, enrol its users and record their grades. In LTI® terms an LMS is a platform.
Widely used examples include Canvas, Moodle, Blackboard, Brightspace, Schoology, Sakai and Open edX. Each implements LTI® 1.3 slightly differently, which is why setup differs per platform — see the LMS setup guides.
An LMS is sometimes called a VLE (virtual learning environment), particularly in the UK.
