Common measure is a four-line stanza pattern, usually in alternating iambic tetrameter and iambic trimeter, with an abab rhyme scheme. It is one of the most familiar English hymn meters, so it is often heard in hymns, ballads, and songs that need a steady, singable rhythm.
It is sometimes called ballad meter, though that term is also used more broadly for related stanza patterns.
Example
The morning light awakes the hill
And silver fills the lane;
The sparrows sing the orchard still,
Then welcome home the rain.