>> I was wonder is there a word for peach in old norse
> In modern Icelandic, it appears to be the feminine noun
> "ferskja". But I haven't found it in an old Icelandic
> source yet.
<Ferskja> is apparently a borrowing of Danish <fersken>.
According to the Ordbog over det Danske Sprog, the word
appears in the Elder Danish period (c.1275-1350) as <pessic>
and in the Elder New Danish period (1500-1700) as
<persik(e)> and <pirssen>; the modern form <fersken> was
influenced by Low German forms of German <Pfirsche>,
<Pfirsich(e)> and by other Danish fruit-names in <-en>.
Thus, Ic. <ferskja> pretty much has to be strictly modern.
The fruit is mentioned in Old French work as early as the
late 12th century, so I expect that speakers of Old Norse
must have encountered it at some point, but it was not at
home in the north, so there may never have been an ON word