In serial numbers etc., there are many cases where you can't tell if the intended character is a number or a letter. For example, the number 0 and the letter O, the number 1 and the letters l or I, and so on.
Is there a name for this concept/problem?
Background: I'm writing a spell corrector for my search engine that handles this situation. I'd like to know what this concept is called so I can document it properly.
Best Answer
A homoglyph is a character identical or nearly identical in appearance to another, but which differs in the meaning it represents.
Wikipedia has a detailed article on homoglyphs as well as one on IDN homograph attacks where phishers take advantage of this property to mislead their victims.
As for your spell-corrector, you should be able to class such occurrences under something along the lines of homoglyph errors or homoglyph conflicts. However, it's a technical term which might possibly be a little too esoteric for your audience.