1 Wendy: We be free o' our pursuers, cap'n!
2 Long Tom: That be good. Now, let's be seein' what we can be makin' o' this map.
3 Long Tom: Hmmm. It be writ in an ancient hand, usin' a long forgotten secret pirate cipher, but I can be readin' some o' it.
4 Wendy: How so, cap'n?
4 Long Tom: I be studyin' arrrchaic languages!

A cipher is different from a (cryptographic) code. The basic difference is that codes transform information at the semantic level, whereas ciphers transform it at the lexicographic level.

To illustrate: If you wanted to send the message "The treasure is in Tortuga" in a code, you'd need a codebook with pre-agreed encodings of the ideas of "treasure" and "Tortuga" at the very least. If "treasure" maps to "bananas" and "Tortuga" maps to "the moon", then your encoded message would be "The bananas are on the moon". The person receiving your coded message would need to know that the bananas refer to treasure, and the moon refers to Tortuga. Anyone who didn't know those mappings would have no idea what the message was really about, and no conceivable way to discover the meaning from the message itself. (To break such a code, you basically need to steal the codebook or interrogate someone who knows it.)

On the other hand, if you wanted to send the same message by a cipher, you'd apply some sort of pre-agreed mapping to the letters in the message. An example might be to reverse the words and replace each letter with the next letter of the alphabet, which yields: "fiu fsvtbfsu tj oj bhvuspu". Ciphers may look less comprehensible, but they are more liable to be broken using no information but that contained in the message itself. In this case, the letter "f" appears several times. The most common letter in English text is "e", so we might guess that "f" represents "e" - which in this case is true. A variety of such techniques can crack pretty much any cipher invented before about 1950 and the advent of computer cryptography.