is eating one time called as ekhasna
Yes. Ekashana (also spelled Ekāsana or Ekashan) means eating only one meal in a single sitting during daylight. It focuses on limiting how much and when you eat, not on a special recipe. The meal is taken once, and usually before sunset; leftovers are avoided and water is typically limited or taken only with the meal, depending on tradition.
Note: interpretations differ slightly between Digambar and Shvetambar communities, especially regarding whether water is allowed and exactly when the meal should occur. In general, both traditions observe one daytime meal, with stricter practices often seen in Digambar contexts.