Expatiate upon Definition 1 of 2Pro Tip 1/3Academic Tone Used in formal or educational contexts to dive deeper into topics. The scholar was invited to expatiate upon her findings at the symposium. Pro Tip 2/3Not for Casual Use Avoid in everyday casual conversations as it can sound too formal or pretentious. It's uncommon to expatiate upon weekend plans with friends. Pro Tip 3/3Attention to Detail Implies giving a thorough explanation or analysis, not just an overview. In her thesis, she expatiated upon every aspect of the policy.