Editing or writing something and can’t find a word in Merriam-Webster, American Heritage, or the Oxford English Dictionary? Don’t freak out and don’t (necessarily) delete it.
Some slang words (fleek, Brexit, and unicorn–in the sense of a unique individual–to name a few), industry-specific terms, and obsolete words may not be found in conventional sources. But does that mean you should hit backspace? Read on:
From the Macmillan Dictionary blog:
Sometimes you’ll see a word you’re not sure of, so you look it up in a dictionary – and lo and behold, it’s missing. You may conclude it’s not a ‘real word’, or maybe not even a word at all. But this is premature.
Most words that people look up but fail to find in a dictionary are words – they just don’t happen to be in that dictionary.
This is especially likely with rare, obsolete, technical, slang, and very new words.
No English dictionary includes every single word – not even the Oxford English Dictionary. The OED is a historical reference work that records the English lexicon from its earliest days, but it doesn’t rush to add new and emerging usages, preferring to wait a few years to see if they become more established in the language. Nor does the OED – or any other dictionary – include every word from the many sublanguages, dialects, and specialist lingos: this would be an impossible task.
Continue reading here.