How well do you know what these letters stand for?ESLUFOETA

ESL -  English as a second or foreign language is the use of English by speakers with different native languages. (Британский, как 2-ой язык для говорящих на различных своих языках)
UFO - НЛО (Unknown Flying Object)
UFO -  are an English rock band that was formed in London in 1969.
They became a transitional group between early hard rock and heavy metal and the new wave of British heavy metal. 
Eta (, ) -  is the seventh letter of the Greek alphabet.
ETA  -  Estimated time of arrival ожидаемое время прибытия.
ETA Systems -  компания по производству суперкомпьютеров.