Sabbath ends at sundown on Saturday. If the women waited till the end of Sabbath, it would've been on Saturday night.
However, it is dark at night, too dark to do work in a tomb. So the women had to wait until daybreak on Sunday morning, when there would be enough light. And they wanted to get there as early as possible, since they were dealing--so they thought--with a body that had been dead since Friday afternoon.
In a very closed sense you are correct. However, that ignores the greater context of what is recorded, and in the light of the context is an incorrect understanding. Words mean things and context provides the understanding of the desired definition of words. BTW, there is nothing in the gospel narratives indicating that the women were carrying lamps, nor were Peter and John when they went to the tomb. This would make sense if it were the daylight hours of Sunday, not the night time hours of Saturday night.