After weight on a product there is an "e" , what does it mean?

It means that the average weight of the product is as specified on the packaging. However the weight of each individual pack may vary slightly.

Because of the packaging process it is accepted that it is not always possible for every packet to have exactly the same weight of product.

In these cases the packaging shows the average weight of the product with a big E next to it.

The manufacturers have to comply with 3 rules when packing items in this way.

1. The actual contents of the packages should not be less, on average, than the stated quantity;

2. The proportion of packages which are short of the stated quantity by a defined amount (the “tolerable negative error” or TNE) should be less than a specified level;

3. No package should be short by more than twice the TNE.

The TNE varies depending on the average weight of the product. For products up to 50g the TNE is 9% of the average quantity. For items over 15kg the TNE is just 1%

The Department of Trade and Industry site says this about the E mark:-

"The E-mark.

The E-mark, when placed on a package, is a declaration by the packer that the contents comply with the average system Directives (Directive 75/106/EEC and Directive 76/211/EEC). As such, it acts as a metrological passport throughout the EEA, assuring free access, so far as metrological requirements are concerned, to all EEA markets. There is no requirement for packages to be labelled with the E-mark, which is entirely optional for the packer. But the Regulations prohibit its use on packages which do not meet certain criteria.

Where used, the E-mark must be at least 3 mm high and applied to packages in the same field of vision as the indication of the nominal quantity. The technical specifications of the E-mark are shown in Schedule 4 of the Regulations.

In order to qualify for E-marking the package must: - have been packed in conformity with the three packers’ rules, and - have a nominal quantity between 5 g or ml and 10 kg or L (inclusive)

Should a packer wish to export E-marked packages from the UK (regardless of whether they are being exported direct from the UK or have first been imported with the aim of exporting them) he must provide the relevant local trading standards department with a notice identifying the premises where this activity is taking place, prior to exporting or importing the packages. "
e is just an abbreviation for 'net' weight
I think it means net weight, and that the product is sold in the European Union. The symbol is not used in the US.
european standard
I think it means net weight.
the e is for estimated, as a statement that the exact weight of the item can't be guaranteed. It just wouldn't be practical to try and weigh every package and its contents as they went out.
average weight - give the points to the chap with the link!
The 'e' stands for estimate as by law then they don't have to have the exact weight stated, i think they can b 2 mg either side. If they do not put this little symbol on and the weight is not 100% accurate you can sue the firm for false advertising on the packaging.

Thus the 'e' acts as a kind of insurance policy for the manufacturer.
when there was the conversion from imperial to metric weights there was more of every product to make the units up to an even amount, it means extra