Albert Barnes Commentary Acts 20:9

"And there sat in the window a certain young man named Eutychus, borne down with deep sleep; and as Paul discoursed yet longer, being borne down by his sleep he fell down from the third story, and was taken up dead." — Acts 20:9 (ASV)

And there sat in a window. The window was left open, probably to avoid the malice of their enemies, who might otherwise be disposed to charge them with holding their assemblies in darkness for purposes of iniquity. The window was a mere opening in the wall to let in light, as there was no glass known at that time; and as the shutters of the window were not closed, there was nothing to prevent Eutychus from falling down.

The third loft. The third story.

And was taken up dead. Some have supposed that he was merely stunned by the fall and that he was still alive. But the obvious and therefore the safest interpretation is that he was actually killed by the fall and was miraculously restored to life. This is an instance of sleeping in public worship that has some excuse. The late hour of the night and the length of the services were the excuse. But, though this often happens now, yet how seldom is a sleeper in a church provided with an excuse for it. No practice is more shameful, disrespectful, and abominable than that common practice of sleeping in the house of God.