A dl is a decilitre
or 1/10 of a litre
or 10 ml.
or 10g of liquid
The dl is used on the continent of Europe more than in England where ml and grams have just about taken over from pounds and pints.
It is now illegal in GB to sell goods in pounds and ounces and the only liquid allowed to be sold in pints is Beer in a Bar where metric measures are illegal, the glass has to be government stamped as a legal measure.