soapbox

Etymology

soap + box. The figurative use of the word derives from the fact that soap products in the US used to be commonly transported to stores in large wooden boxes. It used to be common for individuals to give impromptu rally speeches to their neighbors by finding something to stand on like a soapbox.

noun

1. (literally) A crate for packing soap.
2. (figurative) Any physical or media platform which gives prominence to the person on it and the views they espouse.
   The madman obtained a soapbox which he stood on at the corner of Broadway and Wall street, to shout out his prophesy of the end of the world.
   Bernhard's last appearance on a late-night talk show was a handy soapbox to expound on his political message of patriotism, nationalism, and populism. 2013, Robert F. Ely, Candidate for President, page 25
3. (figurative) A talk about one's pet topic (or the topic itself), especially when only tangentially relevant to an ongoing discussion.
   He's been on his soapbox all day about the new football coach.
4. A soapbox car.

verb

1. To give a speech from (or as if from) a soapbox.
   He soapboxed for whales and pressed us to write petitions and demonstrate with him—he as the leader, we as followers. 2011, Phil Wolfson, Noe: A Father-Son Song of Love, Life, Illness, and Death, North Atlantic Books
   […] and various members soapboxed in Hyde Park on Sunday. 2015, Marc Matera, Black London: The Imperial Metropolis and Decolonization in the Twentieth Century, University of California Press, page 80