There is an excellent glossary (English language only) of pallet terminology floating around the internet. I'm not sure where it originally came from, but you can find it here: http://www.palletexpressinc.com/Nomenclature.html (see definition of 'stringer'). You can also find plenty of good drawings of pallets with all the parts labeled by Googling 'pallet stringer' (there is a particularly good one at http://www.acornpi.com/default.php?page=types).