[noun] [C]When the hotel is full, dinner is served in two sittings (= periods in which a number of people eat a meal).I enjoyed the book so much that I read it all at/in one sitting (= without stopping).The portrait was finished after only three sittings (= periods spent by a model being painted).
SITTING
Meaning of SITTING in English
Cambridge English vocab. Кембриджский английский словарь. 2012