Distributed Tracing is the process of tracking and analyzing what happens to a request (transaction) across all services it touches.
- Transaction: request
- Trace ID: unique request identifier
- Trace: entire transaction (across all services)
- Span: logical chunk of work in a given 'Trace'
Spans have parent-child relationships. A parent can have multiple children. The first span is the "root span". Each span has an ID and a pointer to its parent span ID.
Note: this information was found on the Nike engineering blog