What is a group of syllables forming metrical unit called?

A group of syllables forming a metrical unit is called a foot.

In poetry, a foot is the basic unit of rhythm. It consists of a specific pattern of stressed and unstressed syllables. Different types of feet create different meters, which contribute to the overall rhythm and sound of a poem.

Here are some common types of feet:

* Iamb: Unstressed, Stressed (u/)

* Trochee: Stressed, Unstressed (/u)

* Spondee: Stressed, Stressed (//)

* Anapest: Unstressed, Unstressed, Stressed (uu/)

* Dactyl: Stressed, Unstressed, Unstressed (/uu)

For example, the line "The curfew tolls the knell of parting day" has five iambs, making it iambic pentameter.