Bonded equals "low impedance electrical continuity" and also implies that the connection can stand to pass considerable current.
This tests continuity only. Whether it achieves this connection by NEC approved methods is another question.
with keywords like bonded, bonding, bond, etc. Article 100 (which you should search) has definitions.
It's not the same as grounding. Space station wiring can be bonded.
With a few dollars for a transformer and power resistor you can pass heavy current through this connection and check the connection integrity with your meter.