Denshi Jisho — Online Japanese dictionary

lake (in place names)
Suffix 
こすい lake
Common word, Noun 
こはん lake shore
Common word, Noun, No-adjective 
こがん lakeshore; lakeside
Noun, No-adjective 
こしん center of a lake; centre of a lake
Noun 
こてい bottom of a lake
Noun, No-adjective 
こめん lake surface
Noun 
みずうみ lake
Common word, Noun 
こしょう lakes and marshes
Common word, Noun 
こじょう on the lake
Noun 
沼学 こしょうがく limnology
Noun 
沼型 こしょうがた lake type (i.e. eutrophic, dystrophic, oligotrophic)
Noun 
沼生態系 こしょうせいたいけい lake ecosystem
Noun 
沼水質保全特別措置法 こしょうすいしつほぜんとくべつそちほう Law Concerning Special Measures for Conservation of Lake Water Quality (1984)
Noun 

You can also

Look up kanji details for 湖.

Try a Yahoo Jisho search for 湖 .
Try a Goo Jisho search for 湖 .
Try a Google search for 湖 .