► 動詞化合  [かごう]    
meaning:  combine  rank: 3☆ 
水は
水素と
酸素が化合した
物だ ⇨ Water is compound in which hydrogen and oxygen are combined  
(☛ Combine chemically)► 名詞化合  [かごう]    
meaning:  combine  rank: 3☆ 
水は
水素と
酸素の化合物だ ⇨ Water is a compound of hydrogen and oxygen  
(☛ Combine chemically)More examples:- 有機化合物 ⇨ Organic compounds