You don't want to use a variable as a variable name. Dominus has said why much better than I can. Most likely, you want to use a hash to store the information about fruits:

my %fruits = {
    orange => { name => 'Malus',           size => 123 },
    apple  => { name => 'Citrus sinensis', size => 10 },
};
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You can then access your data as

my $fruit = 'orange';
print $fruits{ $fruit }->{name}, "\n";
print $fruits{ $fruit }->{size};
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Also see tye's References Quick Reference for how to use references.