Translation in english to come... In the mean time, the glossary is in french 

building joint
Cuts made between two parts, each part being able to move independently. The joints allow in construction to absorb the possible movements of the work

A milestone, in the context of project management, is the end of a stage, the end of a job. Most of the time, the milestone is also an important event, like signing a contract, launching a product, etc. It can be a component of a project