From Longman Dictionary of Contemporary Englishsports dayˈsports day noun [countable] British English DSSESa day on which the children at a school have sports competitions SYN field day American English
Examples from the Corpus
sports day• Except for a sports day once a year, their activities were limited to parading up and down.• But, on prize-giving for sports day, they were always there.• You are pressed to attend a school sports day. 