Wordnet 3.0
NOUN (1)
1. 
 a 60th part of a minute of arc; 
- Example: "the treasure is 2 minutes and 45 seconds south of here"[syn: second, arcsecond]
WordNet (r) 3.0 (2006):
arcsecond
    n 1: a 60th part of a minute of arc; "the treasure is 2 minutes
         and 45 seconds south of here" [syn: second, arcsecond]