Maidan (майдан) and Euromaidan (євромайдан) are now pretty familiar terms to anyone watching the protests in Ukraine. They're a reference to the maydan, or square, that's become the focal point of the Kyiv rallies, and the European aspirations of those out on the streets.
titushky (тітушки) -- burly guys dressed in sports gear who act as agents provocateurs. They crack down on protesters or provoke clashes with the aim of tarnishing peaceful protests. This video claims to show titushky being bussed by police to a protest site in Kyiv.
Not a completely new, Euromaidan-specific term, "titushky" was coined earlier this year after two journalists were beaten up in Kyiv by a group of athletically built youth. Titushky are named after Vadym Titushko -- one of three men who received suspended sentences over the May attack. Titushko apparently is not very pleased at the association.
Berkut (Беркут) -- riot police. Berkut, which means golden eagle, is the Ukrainian counterpart to Russia's OMON. Berkut stands accused of abuse of force in the violent dispersal of protesters in Kyiv on November 30.
Mark Galeotti, a U.S.-based expert on Russia's security services, has a nice overview of this special police force here, including one of their recruitment videos.
berkutivets (беркутівець) -- a member of the riot police
Bankova (Вулиця Банкова) -- a central Kyiv street, home to the president's office and site of some of the most violent clashes of the last few days, including an attempt by some protesters -- possibly provocateurs -- to smash down police barricades using a tractor.
zek (зек) -- Russian slang for convict, a taunt aimed at President Viktor Yanukovych referring to the time he spent in prison for theft and assault some 40 years ago.
maydan flags -- aside from the ubiquitous blue-and-yellow Ukrainian and EU flags, protesters have been waving other banners, too.
There are the red and black flags of the World War II-era Ukrainian Insurgent Army (UPA), which is revered primarily in western Ukraine for fighting both Nazi Germany and Soviet forces for Ukrainian independence. Others, particularly in the more pro-Russian east, consider the UPA traitors for fighting against Soviet soldiers.
Then there are the red-and-white banners bearing the name of Udar, the party led by boxer-turned-opposition leader Vitali Klitschko, and the blue flags of the Crimean Tatars. Here's a hybrid, EU-Crimean Tatar flag (in the second photo)
"If you're not jumping, you're a Moskal" ("Хто не скаче той москаль") -- Euromaidan protesters often shout this while jumping, but the chant isn't restricted to the protests, as this video of Ukrainian soccer fans on a metro shows "Moskal" is a historical term for Muscovite, now used mainly as an ethnic slur for Russians. Some Russians take offense at being called "Moskals."
"Up yours, Yanukovych, Ukraine's off to Europe!" ("Януковича в жопу, Україну в Європу!") -- another protest slogan, somewhat ruder in the original than our polite translation.
"Shame!" ("Ганьба!") -- often shouted by Euromaidan protesters (євромайданівці)
-- Kathleen Moore and Pavel Butorin