used to emphasize that something happens at the same moment as something else:
He realized, even as he spoke, that no one would ever believe him.
GRAMMAR GRAMMAR evenusually goes before the word or phrase that you want to emphasize because it is surprising• Even Ed was dancing. • Your room is even messier than mine!!! But evenusually goes after an auxiliary verb or modal verb• They have even invited the teacher (NOT They have invited even...). • He can't even spell his own name (NOT He even can't...).even is not used to introduce another clause. Use even if,even though, or even when• Even if it's raining (NOT Even it's raining), we go for a walk every day. • I love you, even when you're nasty to me.!!You can use 'still' with these expressions, but do not use 'but' or 'yet'• Even though we're completely different, we're still great friends (NOT but/yet we're great friends).
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.