palindrome

noun

Etymology: From Ancient Greek παλίνδρομος (palíndromos, “running back again”), from πάλιν (pálin, “back, again, back again”) + δρόμος (drómos, “running, race, racecourse”). By surface analysis, palin- + -drome (compare also velodrome and syndrome).

1. A word, phrase, number or any other sequence of units which has the property of reading the same forwards as it does backwards, character for character, sometimes disregarding punctuation, capitalization and diacritics.

   “The only thing exciting about 2002 is that it's a palindrome.”

2. A poetic form in which the sequence of words reads the same in either direction.
3. A sequence of items that follows the same pattern both forwards and backwards.

   “A conjunct palindrome from notes 5 to 11, D D E F E D D, abuts the only melodically disjunct group E G D (notes 12–14), and at the same time contributes to a melodic sequence with the opening four notes.”

   “The shops opposite were a High Street palindrome — Korean gorocery, courier service, letting abgents, courier service, Korean grocery — and buses passed with noisy frequency.”

4. A stretch of DNA in which the sequence of nucleotides on one strand are in the reverse order to that of the complementary strand