Yes, and it might also be considered a waste of money.
the dose is X pills. you took a large number over that dose. so it was an overdose in its literal meaning, although perhaps some might call it over dosage. Most people think of the word "overdose" to mean "taking more than is safe and you have a bad reaction to the chemicals". There doesn't appear to be a universal interpretation so I would hesitate to tell you one or the other is the only way to think about it, but for me, it is really only an OD if you suffer consequences.
An overdose is simply taking more medication than directed. Side effects have nothing to do with it.
Yes of course.
Anything over the prescribed dose is classed as an overdose. It's not just about death
yes. There may be side effects that you don't notice, such as liver damage. The liver has excess capacity, so much of it could die and you would not notice it now. But you would later if it were needed, or another overdose occurred.
yes, it still is. it is dangerous to take more medication than you should even if you don't notice adverse effects. you are hurting yourself.