lips
唇 centers on the lips as the visible, fleshy border of the mouth. Its meaning is straightforward and concrete.
唇 combines 辰 (which historically represented a shell or a trembling motion) with 口 (mouth) to indicate the lips. The exact semantic role of 辰 is uncertain, but the character has long been used for 'lips'.
The mouth 口 sits below 辰, like the fleshy lips beneath the nose area. Picture the 辰 shape as the upper face and 口 as the lips themselves.
For シン, imagine thin lips pressing together: thin -> シン, and the lips are the thin edge of the mouth.
lip; lips
lips
upper lip
lip reading
cleft lip
harelip; cleft lip
full lips; thick lips
lower lip
inferior labial artery
bilabial
red lips
rounding of the lips; rounded (e.g. vowel)
labialization
rounded vowel
oral herpes; cold sores; herpes simplex virus 1; HSV-1
labial artery
cleft lip and palate
oral character (in psychoanalysis)
oral phase; oral stage
cheilitis; chilitis; chapped lips