How to define and use a list/array of chars using `Serial.print`
You are almost there:


Use a char* instead of char, a char can only contain one character
Use " instead of ' (Thanks Juraj)


Then you get:

const char* months[] =
 {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};