The obvious meaning of Finlandization is "to become Finland". You might be excused for thinking that this is a remarkably useless word -- after all, how often do we speak of, say, Icelandization or Afghanistanization? -- but during the Cold War the term was in heavy use, even though people could never quite agree on what it meant!

The first recorded use of the word was in its German form Finlandisierung, in a 1966 paper written by Richard Löwenthal, a professor of political science at the University of Berlin. By the term, Löwenthal referred to Finland's precarious political position, where it was constrained in its foreign policy decisions by its powerful neighbor the Soviet Union, and Löwenthal feared that West Germany (and more specifically Berlin) might end up in the same position. As preventing Western Europe from falling under the Soviet umbrella was one of the major aims of the United States during the entire Cold War, the term quickly became popular.

Now, it was an article of faith in Finnish foreign policy that Finland was 100% independent and sovereign, an illusion the Soviets themselves wanted to preserve, so needless to say they weren't particularly happy about this usage of the word. Imported into Finnish, the word underwent a small but significant change: instead of the original suomettaminen, a transitive noun for "being turned into Finland (from the outside)", the Finnish media started to use suomettuminen, "turning into Finland (from within)". (This is roughly analogous to the difference between the English suffixes -fication and -zation.) Perhaps more importantly, Finland worked to cast the term in a positive light: the other sacred cow of Finnish policy was neutrality, so thus "Finlandization" came to mean "the policy of neutrality by non-Communist countries under the influence of the Soviet Union", to quote the American Heritage Dictionary's definition. With time, this came to be the dominant meaning of the word.

But no other country ever actually became Finlandized, at least in the original "insidious Commie takeover" sense; the Iron Curtain stayed put until the day it finally came tumbling down. These days, the AHD inserts the word "former" before "policy", and "Finlandization" has been relegated to the dusty filing cabinets of history.