You'll see the word "ki" again and again in this list, and in case you're not too familiar with the concept, I'll try to explain it here and hopefully clear things up. "Ki" is a Japanese concept that is very difficult to exactly explain in English. It is somewhat of a personal energy/life force, although I think it goes beyond that; I'm not going to try to explain further, partially because I don't completely understand myself. :) In any case, in the DB/DBZ series, ki plays a very large role, most notably that is the source of energy that is used to produce those gigantic energy blasts, and is what allows the characters to fly. The characters also learn to "sense" ki, so that they can roughly tell how powerful someone is, who they are, where they are, whether or not they are hurt or dying, whether they are good or evil, etc. So if you see "ki attack" or "ki technique," it is a technique that is used with ki rather than physical techniques like special punches or kicks, etc.
Ki: Means energy.It is the internal energy you generate when you attack something.
Ki-ai: The shout made when foccusing the Ki.
Ha: In the following attacks, 'ha' appears in the name occasionaly. While 'ha' can translate to 'wave', it is also ki-ai people make when focussing their bodies on an attack. Usually, 'ha' doesn't really have meaning, it's just a loud sound made when your fighting.
Ken: This can mean either 'fist' or 'technique.' As in Hokuto no. Ken: It can mean "Fist of the Northstar" or "Northstar Techniques.

Click on Gohan to see
what the attacks do