Wordnet 3.0
VERB (2)
1. 
 have on one's mind, think about actively; 
- Example: "I'm thinking about my friends abroad"- Example: "She always thinks about her children first"2. 
 take into consideration, have in view; 
- Example: "He entertained the notion of moving to South America"[syn: entertain, think of, toy with, flirt with, think about]
WordNet (r) 3.0 (2006):
think about
    v 1: have on one's mind, think about actively; "I'm thinking
         about my friends abroad"; "She always thinks about her
         children first"
    2: take into consideration, have in view; "He entertained the
       notion of moving to South America" [syn: entertain, think
       of, toy with, flirt with, think about]