'Exalted' was introduced during the Alara block.

702.80. Exalted

• 702.80a. Exalted is a triggered ability. "Exalted" means "Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn."
• 702.80b. A creature "attacks alone" if it's the only creature declared as an attacker in a given combat phase. See rule 506.5.

Translation:

• 702.80a. Exalted occurs in response to you declaring a lone attacker.
• 702.80b. A creature is only attacking alone if it was the only one declared as an attacker. If you declare two attackers and one is killed, the remaining one does not get Exalted.