1. (noun) a pale light sometimes seen at night over marshy ground

• friar's lantern
• jack-o'-lantern
• will-o'-the-wisp

2. (noun) an illusion that misleads

• will-o'-the-wisp

1. (noun) a pale light sometimes seen at night over marshy ground

• light
• visible light
• visible radiation

2. (noun) an illusion that misleads

• fancy
• fantasy
• illusion
• phantasy