About
The character "忪" is structured as a phono-semantic compound with the heart radical 忄 signifying its association with mental states and the component 公 serving as a phonetic indicator. In earlier contexts, this character was used to denote feelings of fear or alarm, typically with the pronunciation zhōng. Its semantic application later expanded to include the sense of drowsiness, especially within the compound "惺忪" where it is pronounced sōng, reflecting a transition in its conveyed meanings from alarm to sleep-related states.