Phonological hierarchy.(quoted from wikipedia)

Phonological hierarchy describes a series of increasingly smaller regions of a phonological utterance. From larger to smaller units, it is as follows:
(1)Utterance
(2)Prosodic declination unit (DU) / intonational phrase (I-phrase)
(3)Prosodic intonation unit (IU) / phonological phrase (P-phrase)
(4)Prosodic list unit (LU)
(5)Clitic group
(6)Phonological word (P-word, ω)
(7)Foot (F): "strong-weak" syllable sequences such as English ladder, button, eat it
(8)Syllable (σ): e.g. cat (one syllable), ladder (two syllables)
(9)Mora (μ) ("half-syllable")
(10)Segment (phoneme): e.g. [k], [æ] and [t] in cat
(11)Feature
The hierarchy from the mora upwards is also called the prosodic hierarchy.
Phonologists disagree on the arrangement and inclusion of units in the hierarchy. For example, the clitic group is not universally recognised, and the P-phrase and IU come from different traditions and have different definitions.