This area is for students or parents, especially those that are willing to put forth the effort to learn more, and be a better student, to achieve more ;-)
To help my students I normally assign them 5 new words a day. Whether they open a physical dictionary or go to the links below, the important thing is that they learn and use new words.
dictionary.com - a handy resource with access to multiple dictionaries in one place, especially if you don't have one in the home.
worddynamo.com - great website that will send you (after you sign up for free) an email of a quickie multiple choice test of new words. It's a fun way to learn!
khanacademy.org - Khan's academy - this is the best resource I've found both for kids and parents. You can sign up your little learner, no matter the age, and they can go out there at any time. - they have all sorts of subjects for free, your child can go at their own pace, and it's a marvelous place to learn with videos online, and more. The kids get 'badges' and bonuses within the Khan system and they have more fun.