Can it 'win' this war? After the murder and capture of Israeli citizens by Hamas, experts think Israel will respond with a ground invasion which could rupture the fabric of the entire region.
Israel’s warning as Gaza invasion looms
Threats: One Israeli defence official said that Gaza would be "razed to the ground". Glossary
Palestine - An area located in the Southern Levant region of Western Asia.
Gaza strip - The smaller of two Palestinian territories, home to two million people. It is located on the Mediterranean coast, surrounded by Israel and Egypt.
Hamas - A militant Palestinian organisation, which has controlled the Gaza Strip since 2007. It is listed as a terrorist organisation in the UK.
Reservists - A member of a military reserve force. In peacetime, they have non-military jobs.
Envoy - A representative, usually from a government.
United Nations - An international organisation focused on keeping peace. Its refugee agency, the UNHCR, aims to assist refugees around the world.
Hezbollah - A militant organisation based in Lebanon, classified in the UK as a terrorist group. It has made direct attacks on Israel and is believed to have been responsible for assassinating Lebanon's former Prime Minister Rafic Hariri.
Successor - A person who takes over from someone else, often in a job.