son·net 
(sŏnĭt)
(sŏnĭt)n.
1. A 14-line verse form often in iambic pentameter, having one of several conventional rhyme schemes and usually featuring a shift in mood or tone after the eighth or twelfth line.
2. A poem in this form.
[French or Italian sonetto (French, from Italian), from Old Provençal sonet, diminutive of son, song, from Latin sonus, a sound; see swen- in the Appendix of Indo-European roots.]