Trimeter: a metre in which the line has three sounded beats and one silent beat or rest (<!>), the latter generally at the end of the line:
I have met them at close of day <!>
Coming with vivid faces <!>
From counter or desk among grey <!>
Eighteenth-century houses <!> (Yeats, “Easter 1916”)
The repeated final silent beat gives such verse an awkward, incomplete, thwarted quality, here …