Whitman wrote “O Captain! My Captain!” as an elegy for Abraham Lincoln, and its tone is suitably elegiac. An elegy is a type of poem that centers on the loss of something cherished, and particularly the loss of a beloved individual. As this definition suggests, elegies are characterized by a serious and often very grave tone. Indeed, the very word, elegy, may derive from a Greek phrase that translates as, “woe, cry” (é lege). The speaker expresses his sadness directly in the poem, and particularly through his repeated cry of lamentation, “O.” As but one example, consider the speaker’s mournful words in lines 5–8:

                              But O heart! heart! heart!
                                 O the bleeding drops of red,
                                    Where on the deck my Captain lies,
                                       Fallen cold and dead.

In addition to starting two lines with a mournful “O,” the repetition of “heart! heart! heart!” powerfully expresses the speaker’s mournful mood. On the level of form, Whitman also emphasizes the elegiac quality of the speaker’s lament through the long lines that characterize the first half of each stanza. Consider the first four lines of the final stanza (lines 17–20):

     My Captain does not answer, his lips are pale and still,
     My father does not feel my arm, he has no pulse nor will,
     The ship is anchor’d safe and sound, its voyage closed and done,
     From fearful trip the victor ship comes in with object won

These long lines have a droning quality that mimic the kind of slow, mournful dirges played at funerals. As such, they offer a formal reflection of the speaker’s elegiac mood.