I don't know if anyone uses a BOX, but getting the dictionary font size to change was kind of a pain.

What worked was adding CSSNorm.css to these two folders in internal storage:

Android/data/com.onyx.dict/files/engine-resources/
Android/data/com.onyx.kreader/files/engine-resources/

/* Smaller Wikcionario definitions */
.mw-parser-output,
.mw-parser-output * {
  font-size: 12px !important;
}

Just thought people may want to know this in case they use a BOOX ereader