To espy means to catch sight of something, especially something distant, small, or partly hidden. When a sailor espies land on the horizon after weeks at sea, or when you espy a friend across a crowded cafeteria, you've spotted something that required a bit of looking.

The word carries a sense of discovery and alertness. You don't espy things that are right in front of your face. Instead, you might espy a hawk perched high in a tree, or espy your lost toy peeking out from under the couch. Sherlock Holmes might espy a crucial clue that others had overlooked.

It suggests the satisfaction of finding what you're searching for, like when you finally espy the last puzzle piece that’s been missing, or when a detective espies an important detail at a crime scene. The word sounds a bit old-fashioned today, and you're more likely to encounter it in classic adventure stories than in everyday conversation, but it perfectly captures that moment when your searching eyes finally lock onto what you've been seeking.