Sabbath & Friday
We use “يوم السبت” to mean Saturday in everyday life just like we use “يوم الجمعة” to mean friday. There is no reason to believe it wasn’t carrying same meaning in past. How do we prove a particular meaning is not mutawatir meaning? By pinpointing the time from which the meaning changed. Can you prove it? The burden of proof lies on one who claims that the word wasn’t carrying same meaning in the past.