If you ask around, especially the HR Practitioners, most will associate Dismissal to terminating an employment contract based on misconduct. Termination, on the other hand, will be based on contractual terms (e.g. serving notice period, salary in lieu of notice, etc.)
In the eyes of MOM, Dismissal simply refers to a termination of contract of service by the employer, and it could be due to misconduct, or simply based on the employment terms. In essence, there is no difference between those 2 terms in the eyes of MOM.
What is Dismissal