Tocharian B eñcuwo “iron” and Tocharian A añcu* have been connected to the Iranian words for “iron”, notably Khwarezmian hnčw. On the basis of insights into the patterns of borrowings from Khotanese into Tocharian, it is argued that the Tocharian words must have been borrowed from a preform of Khotanese hīśśana- “iron”. Further, a new etymology is proposed for “iron” that accounts for the variation of this word in Iranian. The fact that Tocharian borrowed the word for “iron” from Khotanese, not from the archaic steppe dialect of Iranian that is the source of many other loanwords in Tocharian, suggests that the contacts between this latter dialect and Tocharian took place before iron became widespread in the region.