# What does String mean in context of counting theory?

What does "String" mean in context of counting theory ? For example :

There are 8 binary strings of length 3 .

What does binary and length signify here ?

Edit : I want to specifically why it is called a String ?

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It says there are $8$ three-letter "words" using the alphabet $\{0,1\}$. Here are a few: $000$, $001$, $010$, $011$, $100$, three more to go. –  André Nicolas Aug 4 '12 at 6:30
@AndréNicolas I edited the question slightly . I want to know why it is called String ? –  Geek Aug 4 '12 at 6:32
For variety. Like a string of beads. "Sequence" is common too, kinda boring. "Word" is freqently used also. All of these terms convey the notion that order is important. –  André Nicolas Aug 4 '12 at 6:35

binary string means $\textit{a sequence of 0's and 1's}$ and the length defines the number of elements in the sequence.
Like $10011$ is a binary string of length $5$, $110011100$ is a binary string of length $9$ etc.