"season following winter, first of the four seasons of the year; the season in which plants begin to rise," c. 1400 (earlier springing time, late 14c.), a special sense of an otherwise now-archaic spring (n.) "act or time of springing or appearing; the first appearance; the beginning, birth, rise, or origin" of anything (see spring v., and compare spring (n.2), spring (n.3)).
The notion is of the "spring of the year," when plants begin to rise (as in spring of the leaf, 1520s). The Middle English noun also was used of sunrise, the waxing of the moon, rising tides, sprouting of the beard or pubic hair, etc.; compare 14c. spring of dai "sunrise," spring of mone "moonrise," late Old English spring "carbuncle, pustule."
It replaced Old English lencten (see Lent) as the word for the vernal season. Other Germanic languages tend to take words for "fore" or "early" as their roots for the season name (Danish voraar, Dutch voorjaar, literally "fore-year;" German Frühling, from Middle High German vrueje "early"). In 15c. English, the season also was prime-temps, after Old French prin tans, tamps prim (French printemps, which replaced primevère 16c. as the common word for spring), from Latin tempus primum, literally "first time, first season."
Spring fever is from 1843 as "surge of romantic feelings;" earlier of a type of disease or head-cold prevalent in certain places in spring; Old English had lenctenadle. First record of spring cleaning in the domestic sense is by 1843 (in ancient Persia, the first month, corresponding to March-April, was Adukanaiša, which apparently means "Irrigation-Canal-Cleaning Month;" Kent, p.167). Spring chicken "small roasting chicken" (usually 11 to 14 weeks) is recorded from 1780; transferred sense of "young person" first recorded 1906. Baseball spring training attested by 1889, earlier of militias, etc.