Merriam-Webster's Essential Learner's English Dictionary

More than 54,000 words and phrases

Coverage of both U.S. and British English and their differences

More than 15,000 idioms, collocations, and commonly used phrases from American and British English

Clarifies definitions with over 74,000 example sentences and phrases

Usage guidance through extensive labeling (old fashioned, technical, informal, humorous, etc.); glosses (restatements to explain example phrases); count and non-count labeling; usage notes; and usage paragraphs