stable being 121mSn, with a half-life of 43.9 years. The relative differences in the number of tin's stable isotopes can be explained by how they are formed during stellar nucleosynthesis. 116Sn through 120Sn are formed in the s-process (slow neutron capture) in most stars which leads to them being the most common tin isotopes, while 122Sn and 124Sn are only formed in the r-process (rapid neutron capture) in supernovae and are less common. Tin isotopes 117Sn through 120Sn are also produced in the r-process. 112Sn, 114Sn, and 115Sn, cannot be made in significant amounts in the s- or r-processes and are among the p-nuclei whose origins are not well understood. Some ideas about for their formation include proton capture and photodisintegration, 115Sn might be partially produced in the s-process both directly and as the daughter of long-lived 115In. Etymology The word tin is shared among Germanic languages and can be traced back to reconstructed Proto-Germanic ; cognates include German , Swedish and Dutch . It is not found in other branches of Indo-European, except by borrowing from Germanic (e.g., Irish from English). The Latin name for tin, , originally meant an alloy of silver and lead, and came to mean 'tin' in the fourth century—the earlier Latin word for it was , or "white lead". apparently came from an earlier (meaning the same substance), the origin of the Romance and Celtic terms for tin, such as French , Spanish , Italian , and Irish . The origin of / is unknown; it may be pre-Indo-European. The suggests instead that came from Cornish , and is evidence that Cornwall in the first centuries AD was the main source of tin. History Tin extraction and use can be dated to the beginnings of the Bronze Age around 3000 BC, when it was observed that copper objects formed of polymetallic ores with different metal contents had different physical properties. The earliest bronze objects had a tin or arsenic content of less than 2% and are believed to be the result of unintentional alloying due to trace metal content in the copper ore. The addition of a second metal to copper increases its hardness, lowers the melting temperature, and improves the casting process by producing a more fluid melt that cools to a denser, less spongy metal. This was an important innovation that allowed for the much more complex shapes cast in closed molds