TASK DEFINITION: Generate a topic word for the given sentence. A topic word is usually the name of a person, place, animal, concept or object the sentence is focusing on.
PROBLEM: teleportation is the supposed movement of matter from one point to another without travelling across the physical space between them.

SOLUTION: teleportation

PROBLEM: tricity is a big centre for tourism.

SOLUTION: tricity

PROBLEM: a nest is place animals build to hold their eggs or provide a place to raise their babies.

SOLUTION:
nest