Monolingual dictionaries utilize the same methodology that you should be using when trying to explain the meanings of lexical terms: paraphrase. By paraphrasing words in the target language, you can not only teach new vocabulary, but more importantly, improve the fluency level of your students with additional contact in English. This methodology provides an effective strategy that enables you to reach students at different proficiency levels: paraphrase a given vocabulary term first for advanced learners followed by intermediate students and finally, for people that are still struggling with language comprehension.
Keep my advice in mind when using AlexCase's suggestions above, as now, you automatically should have three examples for each activity. :)
Eric Paul Monroehttp://www.eric-tesol.com/