line of poetic verse that consists of four metrical feet. In English versification, the feet are usually iambs (an unstressed syllable followed by a stressed one, as in the word be|cause ), trochees (a stressed syllable followed by an unstressed one, as in the word ti|ger), or a combination of the two. Iambic tetrameter is, next to iambic pentameter, the most common metre in English poetry; it is used in the English and Scottish traditional ballads, which are usually composed of four-line stanzas of alternating iambic tetrameter and trimeter.
TETRAMETER
Meaning of TETRAMETER in English
Britannica English vocabulary. Английский словарь Британика. 2012