As others have said, “Lent” can refer to any fasting period in the East. It’s actually a term borrowed from the West in, I believe, predominantly English speaking countries. “Lent” actually comes from an Old English word meaning “Spring” so it properly only refers to the Great Fast, but it’s been adopted to mean “fasting period”. There are really four fasting periods, but the Apostle’s Fast, as others have said, can be pretty short.
What is called in Lent in the West can be called, in the East, “Lent”, “Great Lent”, or “The Great Fast”.
What is called Advent in the West can be called, in the East, “Advent”, “The Nativity Fast”, “St. Philip’s Fast”, “The Advent Fast” or, I’ve heard rarely, “Little Lent”.
The other two Lenten periods don’t really have an equivalent in the West, but the period before the Dormition is called the Dormition Fast, the period before The Feast of Ss Peter and Paul is called the Apostle’s Fast. You’ll hear different terms, so I was just trying to list them…I think I got 'em all.