a ghost word is a word that got started by accident and exists only in a dictionary

Well, yes, and no, Faldage.

A ghostword got started by accident, true, but it does exist in the english language, and that independent existence may or may not be recognized by an english dictionary. Please see definition below.

The best example of a ghostword I can think of off-hand is "Vamoose", a word very common in all the old "cowboy and Indian" movies.

"Vamoose" obviously derives from the Spanish [Mexican] word "Vamos" for "We go" or "Let's go"*.

ghost word
Wordweb Online

A word form that has entered the language through the perpetuation of an error

http://www.annlewis.net/en/GHOSTWORD

* Dictionary.com vamoose
intr.v. Slang va·moosed, va·moos·ing, va·moos·es
To leave hurriedly.

[From Spanish vamos, let's go, from Latin vdmus, first person pl. present subjunctive of vdere, to go.]