everlasting spring; eternal spring
Poetic or literary term for a spring that never ends, often used metaphorically for an ideal, unchanging state of beauty or youth.
This paradise is called the land of everlasting spring.
Her smile is as warm as eternal spring.
Compound of 常 (とこ, 'eternal') and 春 (はる, 'spring'). The prefix 常 is found in other poetic words like 常夏 (とこなつ, 'everlasting summer').