The term 'refrain syllable' refers to a type of poetic meter used in many traditional forms of poetry. It is composed of two syllables, the first of which is known as the 'tra' and the second as the 'SHA'. The tra syllable is usually stressed, while the SHA syllable is usually unstressed. This type of meter is often used in songs and other forms of poetry to create a rhythmic pattern that helps to emphasize certain words or phrases.