A tenor is a type of classical male singing voice whose vocal range is one of the highest of the male voice types. The tenor's vocal range (in choral music) lies between C3, the C one octave below middle C, and A4, the A above middle C. In solo work, this range extends up to C5, or "tenor high C".
Thanks all - i thought it must be that but not a very accurate clue - it was just 'range of voice' and I thought it referred to a term for the whole range of a voice - the scale etc - not just one tone ! Anyway - many thanks