Related Clues:

• Second word in many limericks
• "That was a long time ___"
• "... and seven years ___ ..."
• "... and seven years ___"
• "___ upon a time ..."
• ___ around the bases
• With 1-Down, every seven days
• "... __ and for all!"
• Start of an epic spaghetti western
• At some past point
• '... bitten, twice shy'
• Gone, past, since
• On just one occasion
• On a single occasion only
• Just as a single occurrence