átlag

Noun

 * 1)  average the arithmetic mean
 * 2)  average any measure of central tendency, especially any mean, the median, or the mode

Usage notes
It normally forms compounds with the subsequent noun in the sense “constituting the average”; see the compound words listed at Derived terms (taken from Magyar értelmező kéziszótár and Magyar helyesírási szótár, although the latter supplies two examples for the form spelled in two words, see the Adjective entry below). Otherwise, its spelling in two words in nonstandard, though not uncommon. In the true adjectival sense “neither very good nor very bad; rated somewhere in the middle of all others in the same category”, the adjectival form is used.

Adjective

 * 1)  average constituting the average

Declension
It is indeclinable as an adjective since it is used only attributively.