Possible Clues:

• Begun, as a town: Abbr.
• Approx.
• Abbr. found on some corporate logos
• Part of ETA: Abbr
• Abbr. on a college entrance sign
• Abbr. on a company sign
• Abbr. on a town sign
• Letters often preceding a year
• Since, for short
• Abbr. on a Heinz ketchup label