Definition:Sequence/Empty Sequence

Definition
An empty sequence is a (finite) sequence containing no terms.

Thus an empty sequence is a mapping from $\varnothing$ to $S$, that is, the empty mapping.

Thus by definition an empty sequence is a (finite) sequence whose length is $0$.

Also known as
An empty sequence is also known as a null sequence.

However, this term is not recommended as it is also in general use to mean a number sequence which converges to a limit of $0$.