Horizontal pistons can indeed function outside of internal combustion (IC) engines, as demonstrated in applications like pumps and steam locomotives. The discussion highlights the importance of understanding the context of the question, particularly the phrase "outside of an IC engine." Clarification on terminology is essential for accurate interpretation and discussion. The conversation emphasizes that asking questions is a sign of engagement and curiosity, rather than a lack of understanding. Overall, horizontal pistons have versatile applications beyond traditional engine use.