# What is an ABC Word™?

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.

If a word conforms to a special rule, I call it an ABC Word™.
Your mission, should you choose to accept, is to find the rule that decides whether a word is an ABC Word™ or not, and why they are called so.

ABC Word™ Non-ABC Word™
PYJAMAS TROUSERS
TWEET POST
FROLIC WORK
WHEN HOW
COLORFUL DRAB
SPASM PEACEFUL
FULFIL NEGLECT
TENT HOUSE
GAMMA ALPHA

CSV Version:

ABC Word™,Non-ABC Word™
PYJAMAS,TROUSERS
TWEET,POST
FROLIC,WORK
WHEN,HOW
COLORFUL,DRAB
SPASM,PEACEFUL
FULFIL,NEGLECT
TENT,HOUSE
GAMMA,ALPHA


Hint:

Maybe assigning numbers to the letters will help you see a pattern.

The solution is:

Assign each letter a number from 1-26: A=1, B=2 etc

Next we

group letters that are equivalent modulo 3. Thus we have three groups ADGJMPSVY, BEHKNQTWZ, CFILORUX

An ABC word is

any word using only letters from one group

• Good show! That's correct! For more clarity behind the name, if you write the letters in a grid format with three columns, the top row reads ABC, and then the rule is that you make words from a single column. Jun 13 at 15:45