Lookups spiked on March 18, 2014.
Russian President Vladimir Putin and Crimean leaders signed a draft treaty that would make Crimea a part of Russia. Under Soviet rule, Crimea had been awarded to Ukraine in 1954, and had remained part of Ukraine following the breakup of the Soviet Union in 1991.
Ukraine's interim president said that Putin was "mimicking the fascists of the last century by annexing the territory of an independent state."
The noun annexation was also used to describe the action in many reports, such as John Cassidy's blog at The New Yorker:
In [Putin's] telling, the annexation of Crimea is merely the righting of past wrongs--the wrongs not only of Western countries but also of the Communist regime, of which he used to be part.
Annex means "to incorporate (a country or other territory) within the domain of a state" or "to take control of (a territory or place)." It comes from the Latin words that mean "to tie" or "to bind to."