This is a good question, since indeed the terms are used in different ways based on the perspective of the speaker and application.
As a one definition, Condition Monitoring is widest definition of monitoring of assets with multiple different ways and different sensors. It includes vibration monitoring, even simple temperature monitoring, oil analysis, different acoustic emissions and infrared heat inspections. Condition based monitoring CbM could mean then same.
Predictive Maintenance is then including also the Maintenance plan of assets, how to run this in practice at factories and it is then using different Condition Monitoring methods.
First step is usually called Preventive Maintenance i.e something that you do in regular intervals. Predictive Maintenance then takes in also more intelligence of analyzing sensor data and deciding the Maintenance based on this, trying to predict when the Maintenance would be needed.
