Denshi Jisho — Online Japanese dictionary

慣れる なれる 1: to grow accustomed (to); to get too familiar with; to get used (to);
2: to become domesticated; to become tame
Common word, Ichidan verb, Intransitive verb 

You can also

Look up kanji details for 慣れる.

Try a Yahoo Jisho search for 慣れる .
Try a Goo Jisho search for 慣れる .
Try a Google search for 慣れる .