- prolongation, protraction, perpetuation, lengthening - the act of prolonging something; "there was an indefinite prolongation of the peace talks"
 --1 is a kind of continuance, continuation
 
- lengthen - make longer; "Lengthen this skirt, please"
 --1 is one way to increase
 Antonyms: shorten
 Sample sentence:
 They lengthen the cape
 
- lengthen - become long or longer; "In Spring, the days lengthen"
 --2 is one way to grow
 Antonyms: shorten
 Sample sentence:
 Something ----s