Your Mac lets you add custom words to its dictionary. This will stop autocorrect from fixing words that are correct but aren't as common, like slang or loanwords.

Utilizing a custom dictionaries helps strengthen your password policies. Learn more from Specops Software about how to build custom dictionaries in your Windows Active Directory password policy.

You can manually add words to your Android device's internal dictionary if it doesn't already recognize them as real words.

Need a definition or synonym on the fly? Dan Frakes shares five ways to access OS X's Dictionary without even launching the program.