what is an ambigram

 Ambrigam : Web definitions
  • An ambigram is a typographical design or artform that may be read as one or more words not only in its form as presented, but also from another viewpoint, direction, or orientation. ...

  • A design that may be read as the same word or phrase (or sometimes two different words or phrases) when oriented in two different ways, usually when reflected in a vertical axis or when rotated through 180 degrees

  • a word, phrase, or sentence written in such a way that it reads the same way upside down as right side up.

  • These are words that, when flipped upside down, legibly spell either the same or a completely different word.  The ClueMaster frequently uses Ambigrams as clues.