Accent is the phonetic prominence given to a particular syllable in a word, or to a particular word within a phrase. When this prominence is produced through greater dynamic force, typically signaled by a combination of amplitude (volume), syllable or vowel length, full articulation of the vowel, and a non-distinctive change in pitch, the result is called stress accent, dynamic accent, or simply stress; when it is produced through pitch alone, it is called pitch accent; and when it is produced through length alone it is called quantitative accent. English has stress accent.
A prominent syllable or word is said to be accented or tonic; the latter term does not imply that it carries phonemic tone. Other syllables or words are said to be unaccented or atonic. Syllables are frequently said to be in pretonic or post-tonic position; certain phonological rules apply specifically to such positions. For instance, in American English, /t/ and /d/ are flapped in post-tonic position.
Some languages combine stress accent and pitch accent, in that accented syllables are both dynamically prominent and may have more than one tone, whereas unstressed syllables do not carry tone. An example of this is Serbo-Croatian accent. Such systems are typically called accent or pitch accent, because the latter term is not well defined.