Denshi Jisho — Online Japanese dictionary

初日 はつひ New Year's Day sunrise
Noun 
初日 しょにち first or opening day
Common word, Adverbial noun, Temporal noun 
初日の出 はつひので first sunrise (of New Year)
Expression 
初日が出る しょにちがでる to achieve one's first victory after a string of losses (in sumo)
Expression, Ichidan verb 
初日を出す しょにちをだす to achieve one's first victory after a string of losses (in sumo)
Expression, Godan verb with su ending 

You can also

Look up kanji details for 初日.

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