The Basic Metrical Feet (based from classical languages) --> were based on the length of time taken to pronounce each syllable, which were categorized according to their weight as either long syllables or short syllables. These are also called heavy and light syllables, respectively to distinguish from long and short vowels.
The foot is often compared to a musical measure and the long and short syllables to whole notes and half notes.
In English poetry, feet are determined by emphasis rather than length, with stressed and unstressed syllables serving the same function as long as short syllables is classical meter.
Metrical Foot --> is a group of 2 or 3 syllables forming the basic unit of poetic rhythm.