The tercet is a poetry form with Italian roots. One of the most famous examples of the tercet form is Dante’s The Divine Comedy. The Divine Comedy was composed of three line stanzas. Every first and third line ended with a rhyme. This is the classic form of a tercet: a three-lined poetic stanza in which the first and third lines rhyme and the second line is a blank (unrhymed) line.
Today, we call this rhymed form an enclosed tercet because the two rhymed lines enclose the blank line. Most modern tercets employ unrhymed or blank verse. An even more stringent form of the tercet is the Sicilian Tercet. The Sicilian Tercet incorporates the enclosed form, but also requires that the poet write in iambic pentameter.
The tercet is rarely a complete poem in itself. Instead, poets write multiple stanzas of tercets to create longer works. A famous English example of a poem using tercet stanzas is Percy Shelley’s Ode to the West Wind, which includes:
The winged seeds, where they lie cold and low,
Each like a corpse within its grave, until
Thine azure sister of the Spring shall blow
The triad is a specific form of tercet. The origins of the triad are Irish and Welsh. A triad is a poem composed of three tercets. It is a consideration of three things and their effect on a person. Welsh versions of the Arthurian legends make heavy use of this form.
Here is a smaple triad that I have written:
My favorite glass folds upward
Three curved echoes
Growing large enough to hold comfort
My blender can spin ice to powder
Gentle as snow in my hair
Eager to provide relief
Parrot Bay and pina colada mix
Turn snow to sweet cold liquor
And I can smile now
The triad is one of the lesser know poetry forms, but it is an enjoyable outlet for expression. You can add as much challenge as you wish. You can simply write in three-line stanzas or you can use iambic pentameter and enclosed tercets if you wish to increase the writing challenge.