a string that has no elements
a string that has no length or value
a string with a length of zero
a string with zero length, while null is undefined
A sequence of characters whose length is zero, i.e. there are no characters in the string.
Analogous to the empty set in set theory, the empty string is a character string of length zero.
The empty string is the unique string of no characters over some alphabet Σ, and is denoted ε or λ. The length of this empty string is 0.