sonet

As nouns the difference between terms and sonet

is that terms is while sonet is nap.

As nouns the difference between sonet and ballad

is that sonet is nap while ballad is a kind of narrative poem, adapted for recitation or singing; especially, a sentimental or romantic poem in short stanzas.

As a verb ballad is

(obsolete) to make mention of in ballads.

As an abbreviation SONET

is Synchronous Optical Networking

As a noun idyll is

any poem or short written piece composed in the style of Theocritus's short pastoral poems, the Idylls.