Trisyllabic foot means a foot with three syllables, stresed or unstressed as the case may be. Trisyllabic feet are not as popular as disyllabic ones. Trisyllabic measures from a verse by themelves, or they can be found among disyllabic measures.

[i] Dactyl:

Originally, in Greek, dactyl means ‘finger’. It is a metrical foot consisting of one stressed syllable followed by two unstressed syllables. [ \ x x ]. Just like finger joints, Dactylics were often used in Classical verse, but not often by English poets until the 19th century when Scott, Byron, Tennyson, Browning and Swinburne experimented with them. Tennyson, for example, used them in his “Charge of the Light Brigade”. One of the best known instances of dactyllic verse is Browning’s “The Lost Leader”:
Just for a \ handful of \ silver he \ left us,
Just for a \ riband to \ stick in his \ coat-
Found the one \ gift of which \ fortune be\reft us,
Lost all the \ others she \ lets us de \ vote.

Dactylics are not unusual in the light verse, as in these ‘Railway Dactyls’ by G. D.:
Here we go \ off on the \ London and \ Birmingham,
Bidding a \ dieu to the \ foggy me \ tropolis!
Staying at \ home with the \ dumps in con\firming’ them:-
Motion and \ m’irth are a \ fillip to \ life.
The dactyl, like the trochee, produces a falling rhythm.

This is not the natural rhythm of English verse. Hence, poems composed entirely of dactylics are rare. But the dactyl, like the trochee, is often used in combination with other feet to provide counterpoint and to act as a substitute foot.

[ii] Anapaest:

The word has originated from Greek whose meaning is ‘beaten back’. It is a metrical foot comprising two unstressed syllables and one stressed. Symbolically it is: x x /. It is opposite of a dactyl. It is a running and galloping foot, and therefore, it is used to create the illusion of swiftness and action. As Coleridge illustrates it in “Metrical Feet”.
With a leap a \ and a bound \ the sw’ift A \ napests throng.

Originally, it was a martial rhythm used in Greek verse, and was adapted by the Romans for drama. In English literature, it is mostly found in popular verse until early in the 18th century. Thereafter it was used fairly frequently for ‘serious’ works by poets like Cowper, Scott, Byron, Morris and Swinburne. In the 20th century, Belloc, Chesterton, Masefield and Betjeman have all employed it successfully. Most poets at some time or another have occasion to use anapaests in combination with other feet. A famous anthology piece which illustrates the anapaestic rhythm is Byron’s “Destruction of Sennacherib”. The following example comes from William Morris’s “The Message of the March Wind”:
But lo, \ the old inn, \ and the lights, \ and the fire and the fidd\ler’s old tune \ and the
sh’uff\ling of feel; soon for us \ shall be qui\et and rest \ and desire, And
tomor\row’s uprising to deeds \ shall be sweet.

[iii] Amphibrach:

The word has originated from Greek whose meaning is ‘short at both hands’. It is a metrical foot consisting of a stressed syllable flanked by two unstressed ones: x / x. It is not common in English verse and seldom indeed functions as the main foot of a poem, However, occasional amphibrachs (mixed with other feel ) occur quite often in stress groups. Matthew Prior’s “Jinny the Just” is a fairly well-known instance of a poem which has a basis of amphibrachs. This is the first verse:
Releas’d from \ the noise of \ the Butcher\ and B’aker Who, my old\ Friends be thanked,\ did seldom\ forsake her And from the\ soft Duns of\ my Landlord\ the Q’uaker,

Many three-syllable words in English are amphibrachs. For example, dependent, arrangement, confusion, etc.

[iv] Bracchius:

A bracchius has one unstressed syllable, followed by two stressed syllables. Symbolically, it is: x//. It, thus, has the effect of a rising rhythm, which then becomes strong.

[v] Antibracchius:

It is the opposite to of a bracchius. It has two stressed syllables, followed by unstressed syllable. Symbolically, it is //x. It, thus, has a faling rhythm, which has a great touch of grief or pity in it.

[vi] Cretic \ Amphibracer:

The word has originated from greek whose meaning is ‘long at both ends’. It is the opposite of an amphibranch, thus:\x\. it is also known as the Cretic foot. It is believed to have originated with the Cretan poet Thaletas (7th C.BC.). Rare in English verse, except when mixed with other feet. Tennyson used it in “The Oak”.
L’ive thy Life
Young and old,
Like you oak
Bright in spring,
L’iving g’old.

Coleridge described and imitated:
First and Last\ being long\ middle, sh’ort\ Amphimacer
Strikes his thun\ dering hooves\ like a proud\ high-bred Racer.

In the second line the pattern is not so regular, and unless ‘like a’ is counted as one syllable and ‘-bred’ is unstressed the meter does not really fit.

[vii] Tribrach:

Ethmologically, the word has originated from Greek whose meaning is ‘set of three’. It is a metrical foot containing three unstressed syllables: x x x. Usually, it is used as a resolved iamb or trochee and seldom found as an independent foot.

[viii] Mobossus:

A mobossus is the opposite of tribrach. It has three stressed syllables. It has a highly emphatic note.