I'm looking for a literary/poetic term

What is it called in literature or poetry when a particular word or phrase is used repeatedly, usually at the beginning of a line or sentence, for emphasis? For example, the word “who” in the famous Ginsberg poem “Howl.”

For years I thought the term for this was apostrophe, but it turns out that’s something completely different.

Anaphora, I think. You might have been thinking of epistrophe, which is the repetition of a word at the end of a sentence/line/phrase.

I guess that’s the one. Thanks!

The apostrophe/epistrophe angle makes sense.

Bobby Sherman with Tom Bahler took it to the lowest common denominator:

O Apostrophe, why do people abuse you?
To form a plural is not how to use you.
You show that “Rita’s” is what belongs to Rita,
And closing a quote is also on your Vita.
You’re a possessive little thing, in contexts urban and rural,
So why, O why, do people try to make you plural?

The Sherman/Bahler song is not an example of anaphora. The repetition has to be the same word at the beginning of different clauses. The repetition of “who” in the poem “Howl” is an example of anaphora.