non-word

noun2

1. •
   Any sequence of sounds or letters which is not considered to be a word, whether through an accidental gap (for example, phextapher-styphren) or through a systematic gap (for example, fssstpklyitnbkdv).

   • This linguistics textbook, like many others, precedes nonwords with an asterisk; for example, *narbletome.
2. •
   (informal) Any term that is not among the words of a language as those have often traditionally been defined by nonlinguists (for example, having syllables, and having come from centuries-old predecessor words): thus, an abbreviation, acronym, initialism, alphanumeric symbol, number written in digits (Arabic numerals 0 to 9), or logographic symbol.

   • In their glossary, they were using a convention where the words were in blue font and the abbreviations and other nonwords were in purple font.