also: えっへん
interjection
Onomatopoeic interjection for clearing one's throat, often to draw attention, express self-importance, or signal a pause before speaking.
えへん、それでは発表を始めます。
Ahem, well then, I'll begin the presentation.
彼はえへんと咳払いをしてから話し出した。
He cleared his throat with an 'ahem' and then started talking.
咳払い is the noun for the act of clearing one's throat, while えへん is the onomatopoeic interjection representing the sound itself.
Onomatopoeic; imitates the sound of clearing one's throat.