Reply To: Shemoneh Esrei – starting with minyan

The change in name from Shemone Esrei to Amidah is because this tefila is the Amidah tefila, the one tefila that mandates standing. The name shemone esrei, although used even for the shabbos and yom tov amidah tefila, is obviously only for the weekdays. So to make the name consistent always, the newer siddurim put in amidah