These are extremely useful on line tools, check them out by clicking on the logos below:

Cambridge is a “must have” classic dictionary.

Oxford is another “must have” classic dictionary.

“Merrian Visual Dictionary helps you learn English in a visual and accessible way. It is designed to help you find the right word at a glance.”

“This reverse-dictionary lets you describe a concept and get back a list of words and phrases related to that concept. Your description can be a few words, a sentence, a question, or even just a single word. Just type it into the box above and hit the “Find words” button. (Keep it short to get the best results.) In most cases you’ll get back a list of related terms with the best matches shown first.”