An Open Book Merriam-Webster defines this as a person or thing that is easy to learn about and understand Cipher M-W defines a cipher as: 2b: a message in code The sentence is an oxymoron. It probably means that she should be easy to understand, but you can only understand her life through her cipher, making her difficult to decipher and understand. More than what was asked, but below is a near-copy of an etymological answer I left on math.SE a while ago, on the etymological origin of the words zero , cipher , and nought. (Sources: Online Etymology Dictionary and Oxford English Dictionary.) zero: circa 1600, (either from Middle Latin zephirum, or French zéro or its source Italian zero, for *zefiro) in any case from Arabic sifr. In many posts and online articles, I come across the usage of eipher. But, I could not get the meaning or history of this word from any sources. The word eipher results many Google search results, but nothing useful found. Examples: Other telegrams in eipher say the rumor is current that he has been strangled. Often I get confused when to capitalise the word state. In the following three different meanings of the word, when should the letter S be capitalized? Synonymous to the words country, nation or Note that the word crypter does not exist (the counterpart of the existing décrypter) I was wondering if there are similar differences in English, spcifically between the words to encrypt / to decrypt , to cipher and to encode / to decode . Wikipedia seems to use encrypt and decrypt as the equivalent of my two first versions. The problem is substitution cipher is a type of cipher, and a cipher aims at concealing the meaning, which is the opposite of what the OP asks for. The word we know today as cipher originated in the late 14th century from the Arabic word sifr, meaning “zero.” At this point in the English language (Middle English) the spellings of words were not yet explicitly defined, and writers commonly substituted i ‘s for y ‘s at will, hence the emergence of cypher as a variant for cipher. We usually use username and password to log in a website, can I use cipher in the situation? Or any difference between these two words? A cypher or cipher is an informal gathering of rappers, beatboxers, and/or break-dancers in a circle, in order to jam musically together. The term has also in recent years come to mean the crowd which forms around freestyle battles, consisting of spectators and onlookers. It is from sense 5 of the word cipher/cypher in the Oxford English Dictionary. Of course the word began life from the French cuffre (modern French chiffre) with an entirely different meaning (the figure, nought) in the 14th century. 5a.