Following the constant flow of developments can be confusing and overwhelming.
As the war in Ukraine continues, here’s a guide to some of the terms you may have heard or seen: What they mean, and why they matter.
DPR and LPR
These are acronyms for two pro-Russian separatist-held regions in the Donbas region of eastern Ukraine: the self-proclaimed Donetsk People’s Republic (DNR) and Luhansk People’s Republic (LPR).
The breakaway territories have been the site of a low-intensity war since 2014, when Russian-backed rebels seized government buildings across the region. The eight-year conflict has left more than 14,000 people dead.
Kyiv and the West insist that the self-declared republics are part of Ukraine, although the Ukrainian government asserts that the two regions are, in effect, Russian-occupied, and refuses to talk directly with either the DPR or LPR.
On February 21, Russian President Vladimir Putin signed decrees recognizing the independence of the separatist territories, and ordered his troops into the region on what the Kremlin called a “peacekeeping” operation.
The move was widely seen by the West as the opening salvo of a larger military operation targeting Ukraine. Three days later, Russian forces invaded the country.
Russia has relied heavily on shelling key Ukrainian cities and towns as it seeks to seize control of locations in the country.
Shelling refers to artillery fire from large guns, and has been used against administrative and residential buildings. Dozens of deaths as a result of Russian shelling have been reported by Ukrainian emergency services.
United Nations officials say more than 500 civilians have died since the invasion, from all causes including air strikes and shelling – though they caution that the true number is likely to be far higher.
Ukrainian President Volodymyr Zelensky has accused Russian forces of shelling indiscriminately since the invasion began. In a message on his Facebook page last Friday, he said Russian troops have been “shelling our people, our children, residential neighborhoods, churches, schools, destroying everything that provides a normal life, human life.”
Humanitarian corridors are demilitarized pathways out of or into fighting zones during a war, which allow people to flee conflict or allow aid to be brought in. They are intended to reduce civilian casualties.
Ukraine has called on global leaders to pressure Putin to open such corridors and “prevent a large scale humanitarian catastrophe” in Ukrainian cities.
But the “humanitarian corridors” being discussed by Russian officials in the Ukraine conflict largely do not meet this description. Ukrainian officials rejected one unilateral Kremlin proposal for evacuation corridors for civilians as an unacceptable non-starter – since most of the routes lead to Russia or its staunch ally Belarus, and would require people to travel through active areas of fighting.
In recent days, hopes for opening up safe evacuation corridors for civilians out of a number of cities have been repeatedly dashed, with Ukraine accusing Russia of attacking escape routes.
“Evacuation through humanitarian corridors is only possible when the ceasefire regime is fully upheld. The Ukrainian side is ready for that,” the Ukrainian Foreign Ministry said in a statement on Monday.
The North Atlantic Treaty Organization is a defense alliance of 30 North American and European nations. According to NATO, its purpose “is to guarantee the freedom and security of its members through political and military means.”
The group was created in 1949, as the Cold War escalated. Its original purpose was to protect the West from the threat posed by the Soviet Union.
Since the end of the Cold War, many former Soviet nations have joined NATO, to the frustration of Putin, who sees it as a threat. Ukraine is not a member of NATO, but has long hoped to join the alliance – something Russia vehemently opposes.
The best-known aspect of the NATO alliance is Article 5 of its treaty, which states that “an attack against one Ally is considered as an attack against all Allies.”
Since Ukraine is not part of NATO, the alliance is not compelled to protect the country in the same way it would if a NATO member nation was attacked; indeed, countries from the alliance have said they have no intention of sending their troops into Ukraine. But many of Ukraine’s neighbors are members, and if a Russian attack extended into one of those countries, Article 5 could trigger direct involvement from the US and other NATO members.
And the alliance can take collective defense measures without invoking Article 5. It has done just that in recent weeks, increasing land, sea and air forces on its eastern flank; Estonian Prime Minister Kaja Kallas has also asked for a more permanent NATO deployment in the Baltics.
A no-fly zone is an area where certain aircraft cannot fly for any number of reasons. In the context of this invasion, it would likely mean a zone where Russian planes are not allowed to fly, in order to prevent them from carrying out airstrikes on Ukraine.
Zelensky has urged NATO to institute a no-fly zone, but NATO’s Secretary-General Jens Stoltenberg has said that it is not an option being considered by the alliance.
If it imposed a no-fly zone over Ukraine, NATO would likely have to step in to enforce it, at the risk of escalating the conflict.
NATO has imposed no-fly zones in non-member countries before, including in Bosnia and Libya, but doing so is always a controversial move because it means getting involved in a conflict without fully committing ground forces.
Putin has said that any countries imposing a no-fly zone will be considered as participants in the armed conflict. If NATO were to do this over Ukraine, it could lead Russia to retaliate against NATO member states.
Javelins and Stingers
The US and other Western nations have been sending key military equipment to Ukraine to assist in its fight against Russia. These include portable anti-aircraft missiles known as Stingers, which are launched by soldiers on the ground to bring down aircraft flying overhead. They allow troops on foot to engage in the battle for Ukraine’s skies.
Portable anti-tank weapons, including US-made Javelin missiles, are also being sent to Ukrainian forces. Also launched by ground troops, these target heavy-duty military vehicles including tanks, and work to slow and disrupt Russian military convoys as they move towards key locations.
The US and NATO have so far sent Ukraine 17,000 anti-tank missiles and 2,000 Stinger anti-aircraft missiles, a senior US official told CNN on Monday.
There are different generations of Stingers that the US produces and US officials have been cognizant of not providing the newest model to the Ukrainians in case they fall into the hands of Russia, which could steal the US technology.
Cluster and ‘vacuum’ bombs
NATO’s Stoltenberg has accused Russia of using cluster bombs as part of its attacks on Ukrainian cities. These are bombs that not only deliver an initial explosion on impact, but also contain multiple smaller bombs that spread over a wide area. They are largely condemned by the international community due to the risk of civilian casualties when they are used in populated areas.
US President Joe Biden’s envoy to the United Nations has separately accused Russia of preparing to use banned weapons, including “cluster munitions and vacuum bombs,” in Ukraine.
“Vacuum bombs,” or thermobaric weapons, suck in the oxygen from the surrounding air to generate a powerful explosion and a large pressure wave that can have enormous destructive effects.
Russia previously used thermobaric weapons in Chechnya with horrifying consequences, according to Human Rights Watch.
A CNN team spotted a Russian thermobaric multiple rockets launcher near the border with Ukraine in late February.
The Geneva Convention, signed in 1949 in the wake of World War II, establishes global standards that must be observed during warfare.
The International Criminal Court (ICC) in The Hague, Netherlands, can prosecute grave breaches of those standards; it has specific definitions for genocide, war crimes, crimes against humanity and the crime of aggression.
The ICC has already launched an active investigation into possible war crimes committed by Russia in Ukraine, including targeting civilian populations, violating the Geneva Convention and targeting specific groups of people.
The US Embassy in Kyiv alleged on Friday that Russia had committed a war crime by attacking the Zaporizhzhia nuclear power plant in Ukraine – the largest in Europe. “It is a war crime to attack a nuclear power plant,” the embassy said on its official Twitter feed. “Putin’s shelling of Europe’s largest nuclear plant takes his reign of terror one step further.”
Sanctions are economic penalties applied by one country against another, or against specific companies or people. Western nations have imposed a stream of tough sanctions on Russia that have stunned its economy since Moscow invaded Ukraine.
Measures imposed on the country have included cutting off Russia’s two largest banks, Sberbank and VTB, from trading in US dollars and removing seven institutions from SWIFT, a global messaging service that connects financial institutions and facilitates rapid and secure payments – essentially isolating Russian banks from the Western financial system.
As a result, the value of the Russian currency, the ruble, and of several Russian companies trading on foreign exchanges, has plummeted.
Key individuals linked to the Kremlin have also been targeted, with Western nations moving to seize their properties or assets.
Of all the Western sanctions imposed Moscow so far, perhaps the most damaging is the removal of some Russian banks from SWIFT.
The Society for Worldwide Interbank Financial Telecommunication was founded in 1973, replacing the telex, and is now used by more than 11,000 financial institutions to send secure messages and payment orders.
SWIFT doesn’t move money around the world. What it does is allow banks to send each other instructions on how to transfer funds across borders. With no globally accepted alternative, it is essential plumbing for global finance.
Disconnecting an entire country from SWIFT is considered the nuclear option of economic sanctions.
CNN’s Ivana Kottasova, Luke McGee, Paul LeBlanc, Zachary B. Wolf and Charles Riley contributed to this article.