Saturnight

plural Saturnights

1. nonstandardrareSaturday evening or night.

   Gatti's series of promenade concerts closed on Saturnight with a special performance for their benefit.

   1879 October 11, “Covent Garden Promenade Concerts”, in The Illustrated London News, London (England), B5xQAAAAYAAJ, page 343

   2 more examples

   But a friend of the family on Saturnight said they felt unable to say a "proper goodbye" because the hospice Charlie was transferred to had been unable to supply the equipment and team of medics Great Ormond Street Hospital (GOSH) insisted was necessary to prolong his life.

   2017, “Charlie Gard: Parents could not say goodbye properly”, in IOL News

   For ages people party on Saturnights, its^([sic]) the night to get out and get all wet and wild, forget about everything and step into our world of musical pleasure ...

   2017, “Versuz on Saturnight”, in iceseven.tv