A word is dead
When it is said,
Some say.
I say it just
begins to live
that day.

A Word is dead.

The poem is written by Emily Dickinson. The title, "a Word is dead" makes the reader curious, because it may seem strange that a word dies; but, as suggested by the capital letter, it is a personification. So, why a word is alive?

The composition is made up of two tercets, even if they are divided only by the full stop and the change of meaning. In the first one the poetess uses the third person, in order to maintaine a distance from the concept. The expression "some say" underlines the distance and ascribe to other people the opening statement. In the second tercet Emily Dickinson uses the first person and expresses her juxtaposition, stating that when a word is said, "it just begins to live".
As far as the semantic level, the stanzas are different each other, too. The first one has blurry temporal references and the subject is unknown, while in the second one the subject is the poetess and the action has a definite time, as you can see in the final line.

The poem is a reflection about the function and the meaning of a "word", considered as a living being. You may deduce so only reading the poem, because in the moment the reader is thinking of the composition, the composition is alive. As well words, unused, are the ones that are dead and you bring them to live and give them meaning by using them in speech or in writing. The emotions and feelings that went into the words being spoken remain, andthe word's meaning remain that way.
The poetess insists on the internal world of a word, which is limited by the cultural, sentimental and intellectual perspective of the thinker. The main theme of the poem is that words never lose their meaning once they are spoken. The intentions they were spoken with remain with the person spoken to as long as the words are remembered.