No; you are right. The 25nm* of 1000-ft-clearence above obstacles is called the MSA - Minimum Sector Altitude (ref PANS-OPS Vol II, Chapter 8 MSA).
*) Obstacles within a buffer zone of 9 km (5 NM) around the boundaries of any given sector shall be considered as well. (Verbatum from the above ref.)
What have you been told?
During my pilot training (in the US) I was told... "If there is one sector, it is called Minimum Safe Altitude. If there are more than one sector, it is called min sector altitude". Never heared about SSA (or is that a British thing?
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