The Chinese word 膨胀 is a compound formed from two characters: 膨, which combines the radical 月 (derived from 肉, indicating flesh or body) with the phonetic component 彭 (péng) to suggest swelling, and 胀, which similarly uses the radical 月 with the phonetic component 长 (zhàng) to convey distension. Together, these characters semantically reinforce each other to create the meaning of expansion or swelling.