Wordnet 3.0
ADJECTIVE (1)
1. 
 continuing through life; 
- Example: "a lifelong friend"- Example: "from lifelong habit"- Example: "his lifelong study of Greek art"[syn: lifelong, womb-to-tomb]
The Collaborative International Dictionary of English v.0.48:
Lifelong \Life"long\ (l[imac]f"l[o^]ng`), a. [Life + long. Cf.
   Livelong.]
   Lasting or continuing through life. --Tennyson.
   [1913 Webster]
WordNet (r) 3.0 (2006):
lifelong
    adj 1: continuing through life; "a lifelong friend"; "from
           lifelong habit"; "his lifelong study of Greek art" [syn:
           lifelong, womb-to-tomb]