also: こんばんわ
interjection
A common evening greeting used from around dusk until bedtime. The は is pronounced わ.
こんばんは、今日はお疲れさまでした。
Good evening, thank you for your hard work today.
Standard kana spelling; usually written in kana. The kanji form 今晩は exists but is less common.
Kanji spelling; less common than kana. May be encountered in formal or older writing.
Irregular kana spelling sometimes used in casual writing or by children; not standard. The reading reflects the irregular kana usage.
Contraction of 今晩は (こんばんは), literally 'this evening is...', from a longer polite expression. The particle は is pronounced わ as a relic of historical kana usage.