お晩 is read as おばん (oban) and means evening.
おばん
oban
ばん
counter for nights
まいばん
every night
こんばん
tonight
さくばん
last night
あさばん
morning and evening
みょうばん
tomorrow evening
ひとばん
all night
そうばん
sooner or later
みっかみばん
three days and three nights
いっさくばん
night before last
まるひとばん
whole night
ばんねん
one's later years