1510s, "make shorter;" 1560s, "grow shorter," from short (adj.) + -en (1); the earlier form of the verb was simply short, from Old English sceortian "to grow short, become short; run short, fail," gescyrtan "to make short."
He shortened his trip due to illness
The manuscript must be shortened
shorten the skirt
shorten the rope by a few inches
In winter, the days shorten