In Co-Counselling the word 'intervention' refers to words or gestures of the Counsellor towards the Client during the session.

It has been originally used in Co-Counselling. However, it has the connotation of a 'power-over' relationship where the client perhaps resists but is expected to go into submission, e.g. The USA intervenes in Iraq.

The word 'suggestion' implies more an equal 'power with' relationship, where the client simply can ignore the suggestion or can ask for a Free Attention Contract, meaning "I do not want any suggestions at the moment".