What does it mean to "second" a motion?

When someone "seconds" a motion, it indicates support for bringing that motion to the floor for discussion and consideration by the assembly. This action signifies that at least one other member believes the motion deserves attention and debate. Without a second, the motion does not move forward, as it shows a lack of interest or desire to discuss the proposed action. This process is an essential aspect of parliamentary procedure, ensuring that only motions with sufficient interest are discussed, ultimately streamlining meetings and decision-making processes.

The other choices do not align with the role of seconding a motion. Voting against or withdrawing a motion would not express support for discussion, while amending a motion pertains to modifying it rather than indicating support for it.