Is a worksheet the same as a datasheet?

No. A worksheet is associated with spreadsheets like Excel. It is an arrangement of columns and rows into which you can put data of different kinds. Worksheets can be quite large, allowing for plenty of rant to do the work. You can put data where you want and put in formulas or data.

A datasheet is also an arrangement of rows and columns, but it only has the amount of columns and rows needed for the fields and records that are being shown, though you can add more. You cannot put formulas directly into the cells. It just has raw data, coming from a table or generated from a query.