The
prime symbol ( ′ ),
double prime symbol ( ″ ),
triple prime symbol ( ),
quadruple prime symbol ( ) etc., are used to designate several different units and for various other purposes in
mathematics, the sciences,
linguistics and
music. The prime symbol should not be confused with the
apostrophe, single
quotation mark,
acute accent, or
grave accent; the double prime symbol should not be confused with the double quotation mark, the
ditto mark, or the
letter double apostrophe. The prime symbol is very similar to the Hebrew
geresh, but in modern fonts the geresh is designed to be aligned with the Hebrew letters and the prime symbol not, so they should not be interchanged.