reference may be given either explicitly (eg A3:B5) or by name (eg myref).
It is possible to define a name to represent more than one range (eg by entering $A$1:$A$3;$C$1:$C$4 in the Assigned To box of the Insert - Names - Define... dialog). In this case ROWS sums the number of rows in each range, irrespective of any duplication of rows.
returns 3; there are three rows in this range, namely rows 3,4 and 5.
returns 3; there are three rows in this range, namely rows 4,5 and 6.
returns 1; D8 is interpreted as a one cell range, with a single row (row 8).
where myref has been defined as the multiple range $A$1:$A$3;$C$1:$C$4, returns 7;