How can you search for definitions online? 

Level: Primary / Intermediate / Secondary

Google has a nifty little feature that we love to tell people about!
The trick here is to type the word define: (with the colon) in front of the word you want, then click Search. E.g. If you wanted to define the word titration, your search would be define: titration. This searches for all the meanings on the web that define your word.

HOT TIP: Reading a few different definitions will help your understanding of the topic. If you don't understand, keep looking for one that uses language at your level.