Hamas is widely and officially recognized as a terrorist organization throughout the entire free world, however often one hears in the media about so-called "Israeli terrorism". The word terrorism is often used very loosely and not in its true meaning. One should distinguish between "terror", which is a general word in English that can be used to used to describe any frightening situation, and the word "terrorism",  which refers to certain specifically defined acts.

First we need to define terrorism, so bear with me on this, as there is some disagreement on the precise definition of terrorism. The definition in UN resolution 1566, is so broad that virtually any military activity can be considered as terrorism (especially since the purpose of the perpetrator is a matter for speculation).

Following this controversial definition, A subsequent UN panel has described terrorism as  "any action [...] that is intended to cause death or serious bodily harm to civilians or non-combatants, when the purpose of such an act, by its nature or context, is to intimidate a population, or to compel a Government or an international organization to do or to abstain from doing any act". This definition is far more practical and usable since it clearly specifies that terrorism involves harm being deliberately inflicted upon civilian or non-combatants. Note also the use of the word intent. In order for an act to be an act of terrorism, it should be proven that it was an intended  act of harming civilians with the purpose of compelling an international organization to do or abstain from doing any act.

Some examples of by-the-book terrorism:

• Sending a suicide-bomber to blow-up in a cafe as part of your political struggle.
  
• Firing rockets deliberately pointed at civilian population, with no military objective, to make a statement that you think the other side has no right to the land.
• Firing rockets or engaging in direct military activity amidst densely populated areas, using the population as a human-shield. This is terrorism since you know the other side is likely and has the right by international law to return fire at you, thus endangering civilians.
• Storing ammunition in a civilian building such as a mosque hoping your enemy won't bomb it because there are civilians there. This is terrorism since you know the other side is likely and has the right to target that building.