Sayounara means "Goodbye" or "Bye." This is a general farewell, but in Japanese, it can sometimes imply a longer separation, so it's not always used for short, temporary goodbyes. For a casual daily goodbye, often a simple "またね" (See you later) is preferred. But it's appropriate for longer partings. "さようなら、先生！" (Goodbye, teacher!).

別(わか)れる時(とき)に使(つか)う言葉(ことば)です。少(すこ)し長(なが)い間(あいだ)会(あ)わない時(とき)に使(つか)う事(こと)が多(おお)いです。「さようなら！」