For the purposes of this Directive, the following terms shall have the following meanings:

(a) worker: any person employed by an employer, including trainees and apprentices but excluding domestic servants;

(b) employer: any natural or legal person who has an employment relationship with the worker and has responsibility for the undertaking and/or establishment; 

(c) workers' representative with specific responsibility for the safety and health of workers: any person elected, chosen or designated in accordance with national laws and/or practices to represent workers where problems arise relating to the safety and health protection of workers at work;

(d) prevention: all the steps or measures taken or planned at all stages of work in the undertaking to prevent or reduce occupational risks.