tetrameter (n.) Look up tetrameter at Dictionary.com
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").