Noteworthy section out of that article:

## The bijective base-26 system [edit]

In the bijective base-26 system one may use the Latin alphabet letters "A" to "Z" to represent the 26 digit values one to twenty-six. (A=1, B=2, C=3, ..., Z=26)

With this choice of notation, the number sequence (starting from 1) begins A, B, C, ..., X, Y, Z, AA, AB, AC, ..., AX, AY, AZ, BA, BB, BC, ...

Each digit position represents a power of twenty-six, so for example, the numeral ABC represents the value 1 × 26^{2} + 2 × 26^{1} + 3 × 26^{0} = 731 in base 10.

Many spreadsheets including Microsoft Excel use this system to assign labels to the columns of a spreadsheet, starting A, B, C, ..., Z, AA, AB, ..., AZ, BA, ..., ZZ, AAA, etc. For instance, in Excel 2013, there can be up to 16384 columns, labeled from A to XFD.^{[3]} A variant of this system is used to name variable stars.^{[4]} It can be applied to any problem where a systematic naming using letters is desired, while using the shortest possible strings.

So it really isn’t that unfamiliar if you ever used Excel