Semordnilap is a name coined for a word or phrase that spells a different word or phrase backwards. "Semordnilap" is itself "palindromes" spelled backwards. Semordnilaps are also known as volvograms,[25] heteropalindromes, semi-palindromes, half-palindromes, reversgrams, mynoretehs, reversible anagrams,[26] word reversals, or anadromes.[27] They have also sometimes been called antigrams,[27] though this term now usually refers to anagrams with opposing meanings. These words are very useful in constructing palindromes; together, each pair forms a palindrome, and they can be added on either side of a shorter palindrome in order to extend it. The longest single-word instances in English are probably of eight letters, of which examples are: * "reporter" / "retroper" (trope v.t chambers' dictionary) * " retraped" / "departer" (trape v.i chambers dictionary) * " rewarder" / "redrawer" * stressed / desserts * samaroid (resembling a samara) / dioramas Other examples include: * gateman / nametag * deliver / reviled * " lamina" / "animal" * dennis / sinned * straw / warts * star / rats * stop / pots * snap / pans * pins / snip * lived / devil * diaper / repaid * smart / trams * spit / tips * live / evil * dog / god * gut / tug * maps / spam * war / raw