Highlight text on your iPhone and iOS helpfully offers to copy or define the highlighted word, among other options. With OS X and iOS growing more and more alike with each passing year, it's a wonder that such functionality has yet to show up on OS X. With PopClip, it does.
PopClip is available in the Mac App Store for $4.99 but is currently discounted at $1.99, £1.49 or AU$2.49 as part of $2 Tuesday. After installing the app, you'll need to allow the app to control your Mac via the Accessibility panel in System Preferences before you get started. PopClip installs as an icon in the menu bar and offers to take you to the Accessibility panel in the Security & Privacy area of System Preferences.
When you're up and running, the next time you highlight text on your Mac, PopClip will display a small pop-up menu with context-specific actions. In addition to the basic cut, copy and paste options, it offers to define a word, correct a misspelled word, open a link or search for the word using Google.
But, wait, there's more! PopClip offers dozens of free extensions that extend the app's functionality. There are extensions to format text, translate text, count characters or words, send text to Evernote or another note app or a to-do app, and many others. From PopClip's menu bar icon, you can uncheck the items you decide that you don't want to use. Also from the menu bar, you can also exclude apps from using PopClip, should you find it interferes with the operation of a particular app.