lecture和seminar区别是意思不同、用法不同。lecture主要是指教育性或者学术性的演讲、引申可指冗长的训斥或谴责。seminar是指(大学教师带领学生作专题讨论的)研讨课、研讨会。

例句：There were as many as 200 people at the lecture.听讲的有200人之多。By the way, how did your seminar go? 对了，你的研讨会进行得怎样？While it will be fun, the seminar also promises to be most instructive.这次的研讨会不仅会有趣，而且有可能会颇具启发意义。