English term (edited): class: primer d\'eso

This looks like Catalan; in Castilian (Spanish) it would be "Primero de ESO".

However, be that as it may, it's a year of study, the first year of secondary education in Spanish (ESO stands for Educación Secundaria Obligatoria: Compulsory Secondary Education). It is normally for children of 12-13. The UK equivalent is Year 8, the second year of secondary school (because in England, as in France, for example, secondary starts at 11 and there is a year less of primary school than in Spain).

http://en.wikipedia.org/wiki/Education_in_Spain#Up_to_Second...
http://en.wikipedia.org/wiki/Education_in_England

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Note added at 13 mins (2012-04-17 15:56:24 GMT)
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I don't know what it would be in Bulgaria. The US equivalent would be 7th Grade.

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Note added at 20 mins (2012-04-17 16:03:09 GMT)
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By the way, I should have said "England and Wales" instead of "UK". In Scotland the equivalent would be S1 and in Northern Ireland it would be Year 9 (just to confuse things further). This is a minefield. Keep in mind that children in Spain are normally 12 when they start 1º ESO.