Translation (Hebrew - עלייה): ascent.

Also, a term coined among jews for the immigrantion to The Land of Israel, which is considered a spiritual ascent (since Israel is the Holy Land). Similarily, Yeridah (descent) is a term for emigration from Israel, and thus spiritual descent.

It's source is in the Torah, from the verse telling how Abraham "went down (yarad) to Egypt".

Nowadays, it's used in modern colloquial Hebrew without any religious context. For example, the former-USSR emigrant looking for "shelter" in Israel would be called an Ole (ascender), while someone leaving Israel to seek fame and fortune in the US would be called a Yored (descender), and it wouldn't necessarily reflect the person's opinions of those countries.

Some politically correct anti-religious enforcement freaks would oppose those terms though and use the literal Hebrew word for "immigration" instead.