2.NounA school break in summer between school years and the break in the school academic year.
3.NounAn easy and pleasant experience.
"This year's inventorying project was a summer holiday in comparison with how it used to go."
4.NounUsed other than figuratively or idiomatically: see summer, holiday: a holiday (holy day or comparable) that falls during the summer; especially, one that celebrates summer or, most specifically, the summer solstice.
"Various religions have a summer holiday; scholars point out that even Christianity's Saint John's Eve partly reflects the Christianization of pre-Christian midsummer festivals."