Reference: Best Practices for Codes and Names of Metadata

Metadata names and codes include the names and codes for:

Accounts.
Attributes and attribute values.
Calendars.
Custom dimensions and dimension values.
Levels.
Text selector columns in modeled sheets.
Versions.
Sheets.

For all metadata names and codes across the model, avoid:

Emojis, which don't display as intended.
Using the same words for different elements, which could create incorrect references in formulas. Example: You use Engineering as a Level name. Avoid using it as a custom dimension name.
Numbers without prefixes or suffixes, such as using 100 as a cost center code. Plain numbers as codes don't provide an indication of the dimension type and can cause data export issues.

There are additional characters and words to avoid when you create names and codes for:

Attributes and values.
Custom dimensions and values.
Levels.
Text selector columns in modeled sheets.

Using these characters and words in the names or codes might create formula errors or other unexpected results because the same characters and words match formula computations or formula elements. Errors and unexpected results are more likely to occur when the characters or words are at the beginning or end of the name or code.