All operators built in to Onyx have corresponding names that are composed entirely of lower case letters and numbers (with the exception of syntax-supporting operators like [). In order to avoid any possibility of namespace collisions with names defined by current and future versions of Onyx, use at least one character that is not a lower case letter or a number in names (for example, capital letters, underscore, etc.). In practice, namespace collisions usually aren't a problem, even if they happen, since the only effect is that the program-defined definition shadows the built in definition during name lookups.