ambigrams

Noun

ambigram (plural ambigrams)

1. A calligraphic design that may be read as the same word or phrase (or sometimes different words or phrases) when oriented in two different ways, usually when reflected along a vertical or horizontal axis or when rotated through 180 degrees.
   • Two nonvisual factors provide dissymmetry and prevent the ambigram from existing in a static equilibrium; most of the letters in an ambigram metamorphose into other letters when reversed; and each of those accompanying sentences provides a different idea of the word's meaning.1992, John Langdon, Wordplay, published 2005, page 52