what is capital punishment ?

some people think that capital punishment only means hanging a person with rope as giving him a penalty of killing

Capital punishment, also known as the death penalty, is a government-sanctioned practice whereby a person is killed by the state as a punishment for a crime. The sentence that someone be punished in such a manner is referred to as a death sentence, whereas the act of carrying out the sentence is known as an execution. Crimes that are punishable by death are known as capital crimes, capital offenses or capital felonies, and they commonly include serious offences such as murder, mass murder, aggravated cases of rape, child rape, child sexual abuse, terrorism, treason, espionage, offences against the State, such as attempting to overthrow government, piracy, aircraft hijacking, drug trafficking and drug dealing, war crimes, crimes against humanity and genocide, and in some cases, the most serious acts of recidivism, aggravated robbery, and kidnapping, but may include a wide range of offences depending on a country. Etymologically, the term capital (lit. "of the head", derived via the Latin capitalize from caput, "head") in this context alluded to execution by beheading.

Fifty-six countries retain capital punishment, 106 countries have completely abolished it de jure for all crimes, eight have abolished it for ordinary crimes (while maintaining it for special circumstances such as war crimes), and 28 are abolitionist in practice.

Capital punishment is a matter of active controversy in several countries and states, and positions can vary within a single political ideology or cultural region. In the European Union, Article 2 of the Charter of Fundamental Rights of the European Union prohibits the use of capital punishment. The Council of Europe, which has 47 member states, has sought to abolish the use of the death penalty by its members absolutely, through Protocol 13 of the European Convention on Human Rights. However, this only affects those member states which have signed and ratified it, and they do not include Armenia, Russia, and Azerbaijan.

this boycotted by many people but now it has become legal
The United Nations General Assembly has adopted, in 2007, 2008, 2010, 2012 and 2014, non-binding resolutions calling for a global moratorium on executions, with a view to eventual abolition. Although most nations have abolished capital punishment, over 60% of the world's population live in countries where the death penalty is retained, such as China, India, the United States, Indonesia, Pakistan, Bangladesh, Nigeria, Ethiopia, Egypt, Saudi Arabia, Iran, among all mostly Islamic countries, as is maintained in Japan, South Korea, Taiwan, and Sri Lanka. China is believed to execute more people than all other countries combined.