Explanation:

- Replace: This command is typically used to search for a word or phrase and replace it with another. It’s broader than just finding a word and can change all instances in one go.

- Find: This is the quickest and easiest way to locate a particular word or phrase in a document. It highlights all instances of your search term and helps you navigate through them.

- Lookup: Generally not a specific command in Word for finding text. It may relate to looking up more information but not directly finding text.

- Search: While similar in concept to "Find", "Search" is not the specific term used in Word commands for this function.