tetrameter (n.)

1610s, from Late Latin tetrametrus, from Greek tetrametron "verse of four measures" (generally trochaic), noun use of neuter of tetrametros (adj.) "having four measures," from tetra- "four" (from PIE root *kwetwer- "four") + metron "poetic meter, measure" (from PIE root *me- (2) "to measure").