The asterisk is usually the wildcard used to represent a number of characters together. Single characters are usually indicated by the hash # symbol (again not 4,4)
Maybe hjk knows something he's not telling us (like intersecting letters).
hjk, When asking for help, it is always best to show what letters you already have as it stops people wasting time thinking of answers that are impossible to fit.
actually thinking about it cancross has a point, there are lots of different wildcards in different applications and systems, as gen2 made me notice wild card is one, you also have star sign, but it's a fairly vague question.