A native Korean word of Old Korean origin. The root is related to the verb 열다 (yeolda, "to open/ripen"), reflecting the season when crops ripen and the sun is at its peak. The suffix -음 nominalizes the concept, giving the sense of "the ripening time."

South Korea's summer (roughly June–August) is defined by intense heat and high humidity, with a distinct monsoon rainy season called 장마 (jangma) typically arriving in late June — making today's scheduled date, June 21st, perfectly timed. Summer is also associated with 보양식 (boyangshik), restorative foods eaten to combat the heat, such as 삼계탕 (samgyetang, ginseng chicken soup). Koreans often greet each other during summer with "더위 조심하세요" ("be careful of the heat").