Is a sequencer the same as a relay?

Excuse me, could you please clarify the distinction between a sequencer and a relay? I understand they both play a role in electrical systems, but I'm not entirely sure how they differ from each other. Could you elaborate on their specific functions and how they are used in various applications? I'm particularly interested in understanding the nuances between the two and how they might be used interchangeably or distinctly in different contexts. Thank you for your time and expertise.