Medical and biological term for saliva; also used for sputum in clinical contexts. In everyday conversation, つば is more common.
Just seeing a lemon made my mouth water.
When saliva secretion decreases, the mouth tends to become dry.
Saliva was collected for testing.
The salivary glands secrete about 1.5 liters of saliva a day.
When you're nervous, saliva production drops and your mouth gets dry.
Standard kanji spelling for the medical/biological term.
Kana spelling used in informal or explanatory contexts, or when the kanji are considered difficult.
From Middle Chinese 唾液 (tʰɑp̚ jiᴇiH, 'saliva'). The kanji 唾 means 'saliva' and 液 means 'fluid'.