(a) "designation" means a written instrument referred to in subsection 3(1);
(b) "employer" includes the trustee under a plan;
(c) "participant" means a person who is participating in a plan established by an employer and who
(i) is or has been employed by the employer, or
(ii) is an agent or former agent of the employer; and
(d) "plan" means a pension, retirement, welfare, or profit-sharing fund, scheme, or arrangement, for the benefit of employees, former employees, agents or former agents of an employer.