Wordnet 3.0
NOUN (1)
1. 
 an amount of time; 
- Example: "a time period of 30 years"- Example: "hastened the period of time of his recovery"- Example: "Picasso's blue period"[syn: time period, period of time, period]
WordNet (r) 3.0 (2006):
time period
    n 1: an amount of time; "a time period of 30 years"; "hastened
         the period of time of his recovery"; "Picasso's blue
         period" [syn: time period, period of time, period]