I love them. Type in the word, and all the information you want shows up. Although there are many on-line dictionaries, my particular favorite is Merriam Webster on line. I can Google any word followed by ‘Merriam’ and it brings up the link to that word. Yes, there is an advertisement (isn’t there always, anymore? -- but they pay for the service!). The ad can be skipped and the rest is fast, and comprehensible. Plus it gives an audible pronunciation of the word! I admit to being a pronunciation challenged person, so this is such a bonus. A medical dictionary and an encyclopedia are also available; however, my next favorite feature after the definition is the video section.
In the video section Merriam Webster editors speak about issues in grammar. If you think the plural pronoun agreement is wrong with indefinite singular antecedent check out Merriam Webster’s Ask the Editor – it’s such a relief! I was so tired of that politically correct usage of 'each has his or her preferences.' It is so nice to write 'each has their preference' without guilt. So Woo-hoo to Merriam Webster!
It is so easy today to be writing at your computer and have the ability to check out words on line so efficiently! There are many, many sources on the Internet for writers, it makes me think I’m living in a wonderful time in history.