There is much speculation flying around as to what the word "Aiki" may mean. The ideas that seem to pop up the most are:
A) Aiki, is a term that is describing a way to understand, lead, manipulate or physically blend with the mind and intentions of an attacker.
B) A body ability that gives it's practitioner great physical power, making them seem unmovable and strangely forceful.
From this, it would sound like a Daito ryu expert feels as if "Aiki" has a lot to do with the ability to lead someones mind.
Here is another remark about "aiki" from an interview with Sugawara Sensei ( http://web.archive.org/web/200212240...kidoTaiji1.htm
"Sugawara said the Founder tried to explain about harmonizing ki; and that was the goal of the Founder's Aikido. "To feel partner's feeling and spirit, then to change and flow . . . to catch partner's spirit, this is the aiki situation," he said. Modern martial arts are too stiff, Sugawara feels, and, unfortunately, Aikido is not an exception."