Yon means “over there” or “in that direction,” pointing to something at a distance but still visible. It's an old-fashioned word you'll mostly find in poetry, historical stories, or deliberately dramatic speech.

You might read in a novel: “Do you see yon castle on the hill?” meaning the castle that's far away but within sight. In Shakespeare's plays, characters often speak of “yon moon” or “yon tower.” The word creates a feeling of distance and sometimes mystery or grandeur, as if the speaker is gesturing toward something important on the horizon.

The related word yonder means the same thing but sounds even more poetic and old-timey: “way over yonder by the river.” While people rarely use yon or yonder in everyday conversation anymore, you'll encounter them in classic literature, folk songs, and historical fiction. When a character uses yon, they're usually pointing toward something far enough away that you'd need to squint or shade your eyes to see it clearly. It's the difference between “this tree” (right nearby) and “yon tree” (the distant one on the far ridge).