The morphological order of a symbol places it into one of three categories:
- Simple Character. A simple character is atomic—it cannot be broken down into any smaller meaningful components. Linguists call this a morpheme.
- Composite Character. A composite character is made of two or more other characters.
- Word. A word is made of two or more characters, placed one after another.
These categories are based on but not faithful to BCI's fundamental rules. They were chosen to aid the lexicographer as they compiled this dictionary.