Re: surely trying to kill someone in a business quarrel isn't terrorism?
Knowing how to make a functional, deadly bomb is not something that is common. Hell, actual terrorists have been known to foul it up.
Actually, with limited electrical knowledge, it's pretty easy to make all sorts of IEDS. In the cabinet in the garage I have enough bits, tools and "chemicals" to make some interesting explosive devices that while low-yield will be enough to kill anyone close to it, perhaps kill others (eg something that knocks out a car's brakes at a certain speed - fairly easy to do these days with little thought and gadgetry). All you have to do is trigger a switch at the right time, and that switch can then do all sorts of things that can result in death.
An explosive doesn't have to be big to kill. I could probably generate enough force with a single stroke from a bicycle pump to propel an item hard enough to kill someone IF it hits them in the right place, is sharp enough etc. Most people know how to make things ignite and 'explode', and it takes little thought to come up with something small but effective. Many people however go for more complex ideas that require a large number of moving parts or electronics, to be sure they get the person they're after. 
A bomb is terrorism, it is not just violence.
No. A bomb is not terrorism, though it may be used by terrorists as part of their plots. However, equating bombs with terrorism could in itself be a form of terrorism, as you're promoting a view that makes people more afraid (ie more 'terrorised') of the world around them and when every little attempt at murder, sabotage etc is called 'an act of terror,' that increases the sense that 'terror is everywhere' and the world is not generally safe. That is what terrorism is; causing people to be afraid.
Use the term as it should be used, don't weaken it by equating some brat having a hissy fit with a group who would rather maim your kids then let you have a peaceful life. By mis-using such words you rob the world of some of its peace.
 I was going to suggest something that I have the parts for already (except the actual payload) in generic devices and components (eg relays and electrical wire), but realised that such a comment could fall under "publishing information of interest to terrorists" or somesuch, at which time it could actually be a crime.
 For the record, my thoughts come from experience, and my experience involves working with volatile chemicals and compounds and having to know the 5 ways NOT to cause accidental ignition, vs the million ways that guarantee ignition.