back-formation
n [U, C] (process of making a) word that appears to be the root of a longer word, eg televise from television 逆构词(该词看来像是某一较长单词的词根, 如由television逆造出 televise); 逆序造词法.
and we have to lower into the ground and haul out of the ground great lengths of drill pipe which are rotated by an engine at the top and are fitted with a cutting bit at the bottom.