According to Dictionary.com, the word "phonetic" indicates anything of or relevant to speech sounds and their production as well as the transcription of speech sounds in written form. The adjective is also used to indicate something that corresponds or agrees with pronunciation, such as phonetic transcription and phonetic spelling, respectively.
Dictionary.com states that the word is also used as a noun to identify the written element representing a sound in Chinese writing. Such an element is combined with a radical to form a character.
According to the Online Etymology Dictionary, the adjective phonetic comes to English from the Modern Latin "phoneticus," which in turn originates in the Greek "phonetikos," which means "vocal."