Family name Sayday (Саидаи 
, Sayday 
) , around the globe, is a very rare cognomen. The cognomen Sayday is characteristic of Myanmar, where it is a very rare surname, Russia, and Canada, where it is an extremely rare surname. Measured by absolute frequency, the name is most common in Myanmar, Russia, and India. Very seldom, Sayday is the forename as well as the last name.