The squiggly red underline that shows up on some words indicates that PowerPoint considers those words to be misspelled! But that’s not always the truth — your spelling may be accurate but PowerPoint merely indicates the spelling error because that particular word may not be part of its vocabulary. Let’s explore this more — PowerPoint considers some medical or legal terms which are not commonly used, as misspelled words. To avoid this, you need to teach PowerPoint to spell those words — in other words, you must enhance PowerPoint’s custom dictionary. Of course, not only can you teach PowerPoint how to spell medical words, but you can also teach the program how to spell words that enhance lexicons in various other subjects such as research, law, computing, etc.