ARBITRARY

To call the relationship between a symbol and its object "arbitrary" is not to say that the connection between the sign and its object is random, but rather that we currently know of no reason why we use that sign rather than some other one.

For example, a sign that brings to mind the concept of frozen water is the word, #ice#. Scholars know of no reason why the string of letters, #i# - #c# - #e# rather than some other string, has come to represent the concept of frozen water, it just has -- this is what arbitrary means.