Searching Dictionaries
The trace command is used to search for words in the CSpell dictionaries.
Command: trace - See which dictionaries contain a word
Trace shows the list of known dictionaries and a * next to the ones that contain the word.
A ! will appear next to the ones where the word is forbidden.

The word is found in a dictionary if a * appears before the dictionary name. 
The dictionary is enabled, (in use based upon the file type), if the dictionary name is followed by a *. 
Options
Usage: cspell trace [options] <words...>
Trace words
Search for words in the configuration and dictionaries.
Options:
-c, --config <cspell.json> Configuration file to use. By default cspell
looks for cspell.json in the current directory.
--locale <locale> Set language locales. i.e. "en,fr" for English
and French, or "en-GB" for British English.
--languageId <language> Force programming language for unknown
extensions. i.e. "php" or "scala"
--no-color Turn off color.
--color Force color
-h, --help display help for command
Using languageId
Search for errorcode
cspell trace --languageId=cpp "errorcode"

The + between error+code indicates that it was found using compound words enabled by allowCompoundWords setting.