'Spring' was named for plants 'springing' from the earth — it replaced the older season name 'lent.'
The season between winter and summer, when plants begin to grow; also, a natural source of water flowing from the ground, or the act of leaping.
The season sense derives from the verbal notion of 'springing' — plants springing from the earth. Old English springan meant 'to leap, burst forth, grow,' from Proto-Germanic *springaną, from PIE *sprenǵʰ- ('to move quickly'). The full phrase 'spring of the year' or 'spring-time' appeared in the 14th century and was gradually