Is the sentence we must forever conduct our struggle on high plane of dignity and discipline a onomatopoeia?

No, the sentence "We must forever conduct our struggle on a high plane of dignity and discipline" is not an onomatopoeia.

Here's why:

* Onomatopoeia: This is a word that imitates the sound it represents (e.g., "buzz," "meow," "crash"). The sentence you provided does not contain any words that imitate sounds.

* The sentence is a statement: It expresses a principle about how to approach a struggle.

Let me know if you have any other questions!