• 講演こうえん — lecture / public speech
• 講義こうぎ — academic lecture
• 講師こうし — instructor
• 講座こうざ — course (series of lectures)
• 講習こうしゅう — training course
• 講談こうだん — traditional storytelling
• 休講きゅうこう — cancelled lecture
• 受講じゅこう — attending a lecture / taking a course
• 補講ほこう — supplementary lecture / makeup class

講 combines the 言 (speech / language) radical with 光 as the phonetic element. It originally referred to gatherings for teaching or explaining doctrines. Today it broadly means lectures, explanations, and organized instruction.