Right
中 supplies the sound — zhōng shifted only in tone to zhǒng (1st → 3rd). Same phonetic family:
钟 (zhōng, bell),
种 (zhǒng/zhòng, seed/plant),
忠 (zhōng, loyal).
中 also offers a mnemonic: a swelling is the centre of the inflammation, the bulge in the middle of the affected area.