Once a while, you will need to search for the meaning of a word, instead of copying the word and searching online, you can find the definitions easily with the Microsoft Word built-in functions. Please see below for details:
Step 1: Select the word or phrase, click the "References" tab from the ribbon;
Step 2: Click "Smart Lookup" in the "Research" section;
Step 3: The definition will appear on the right in the "Smart Lookup" panel.