While Shelley’s speaker wants his words to spur people to action, he also wants them to give people hope; a prophecy of a better future. In this instance, spring symbolizes that hope.

Shelley’s speaker recognizes that his words are the primary way he can fight injustice, so he begs the West Wind to help spread his battle cry to others across the country and spur a revolution.

A lyre is a stringed musical instrument that originated in ancient Greece.

According to multiple gospels in the Bible, Jesus wore a crown of thorns shortly before his crucifixion. The thorns were meant to hurt him and mock his alleged authority. In this sense, the crown of thorns symbolism suggests many things: first, the mockery that Shelley believed the English monarchy had become under George III; and second, the basic nature of pain and suffering in life that began with Jesus’ pain. The mention of blood, too, invokes the blood of Christ along with his salvation, and the salvation of his followers by drinking the representation of his blood during communion. Interestingly, the religious allusions also play into the way Shelley addresses the West Wind (particularly in this section of the poem) with deep humility and prayer, as though the Wind is a god.

Shelley’s speaker laments how he no longer has the energy and vigor to be the revolutionary that he had been when he was younger. In Shelley’s personal life, he did live a life considered revolutionary or scandalous by many, such as praising atheism, taking many lovers, and leaving his wife for Mary Godwin, who became Mary Shelley, the famous author of Frankenstein. In his late 20s, however, when he composed this poem, life had hit him with a series of hardships: his first wife (with whom he had children) died by suicide in 1816, his infant daughter died in 1818, and his young son died in 1819. The world-weary tone employed in this part of the poem, then, may reflect the fact that in recent years Shelley had not been a stranger to tragedy.

By attributing a human emotion (fear) to plants, which aren’t sentient, Shelley employs a technique called anthropomorphism. This involves imbuing objects, plants, or even animals with human emotions, desires, and motivations.

Baiae was a city in ancient Rome located north of the Gulf of Naples. It was known for its luxurious baths and as a place where the rich, famous, and artistic would go to relax and enjoy parties and other more scandalous activities. Baiae had a reputation for being a place of sin, which was further reinforced by the volcanic activity along the coastline. Today, parts of the ancient city have been preserved as monuments, but other parts are completely submerged underwater, which may be what Shelley refers to by the “old palaces and towers” in the following line.

This stanza and the rest of section III describe the West Wind waking up the calm ocean and turning it into a raging, fearsome sea. Wind currents can and do affect ocean currents and can get stronger during the winter months.

Black rain is a type of rain that has been polluted and contains ash, dust, or other particles. In modern terminology, it also refers to rain that gathers soot and falls as part of nuclear fallout, though of course this definition wouldn’t have existed during Shelley’s lifetime.

A sepulchre is a stone tomb. The term also has religious connotations, as a sepulchre can refer to a place where religious artifacts are kept. When taking this second meaning into account, the use of the word could signify a tomb not just for the dying season, but for the dying belief system of a king and society being ousted by revolutionaries. The use of the phrase “congregated might” also suggests religious connotations, as it brings to mind a church congregation.

In Greco-Roman mythology, Maenads are women who grow frenzied drinking wine and worshipping Dionysus (Bacchus), the god of wine known for having a dual nature: kind and freeing as well as cruel and wild. Maenads too have this duality, as they live free in the natural world and worship it, but also devour living animals alive and relish in the bloodlust.

This word is an alternate spelling of airy; in a poetical sense, aëry also meant something that was ethereal or of the air, not just something that was in the air.

A clarion is a type of war trumpet. “Clarion call” as a phrase means to make a request that will spur people to action.

This reference to seeds waiting for spring to awaken alludes to the idea of a rebellion lying in wait to rise up. The term “spring” has been used throughout history to refer to various uprisings and political movements, such as the Spring of Nations in Europe in 1848 or the Arab Spring in 2010.

Though describing leaves, this line contains a poetic device called a metaphor to compare dying autumn leaves with people stricken by pestilence. When Shelley penned “Ode to the West Wind” in 1819, many people in England were actually starving and sickening. England was in the middle of a political upheaval as the aging King George III lost favor and the people demanded parliamentary reform. The country faced unemployment and famine after the Napoleonic Wars of years prior. In August 1819 in Manchester, the Peterloo Massacre took place, where soldiers attacked citizens who were demonstrating. Shelley was forthright in his liberal political beliefs, which are detailed in another poem he wrote during this time period called England in 1819.

Shelley likens dead leaves to ghosts by using a simile, a phrase that uses the words “like” or “as” to show comparison between two seemingly different things. The simile works on two levels: Visually, the dying, fading leaves bring to mind the gossamer, colorless form of ghosts; and symbolically, the dead leaves represent the past, the end of a season. By comparing the wind to an enchanter, Shelley imbues the wind with magical powers, suggesting it is grander and more significant than just ordinary wind.

In Greek mythology, Zephyr (sometimes called Zephyrus) was the god of the West Wind, the gentlest of the four winds. He was known as the messenger of spring.

Shelley begins the poem with an apostrophe, or a direct address to a figure who cannot or does not respond—in this case, the West Wind. Note too how Shelley crafts the rhyme scheme in the poem: the middle of each stanza rhymes with the first and third lines of the next stanza: ABA, BCB, CDC, DED, EE, EFE, etc.

The wind blowing through the forest leaves creates a sound that Shelley compares to music, specifically the sound of the lyre. The sound can be rather emotionally stirring, like music. 

Note the alliteration and consonance of p sounds in "pant," "power," and "impulse," evoking the power of the west wind as well as the pounding power of the wave it generates. 

The last two words in each of these two lines are reversed. The normal syntax would be: "the dead leaves are driven like ghosts fleeing from an enchanter." By reversing the normal order, Shelley imitates the pell-mell, helter-skelter flight of the stricken leaves. Those in back are tumbled into the front by the wild wind, and other leaves behind in the rout will be blown in front of them.