fork (7 facts) - A symbol in an activity diagram indicating splitting of control into multiple threads
join (6 facts) - A symbol in an activity diagram indicating a point where several threads wait for each other. When all threads reach the join, control continues in a single thread
rendezvous (6 facts) - In concurrent programming, a situation where several threads meet and wait for each other
swimlane (4 facts) - A division in a UML activity diagram showing the activities performed by a particular object