Old English and, ond, originally meaning "thereupon, next," from Proto-Germanic *unda (cf. Old Saxon endi, Old Frisian anda, Middle Dutch ende, Old High German enti, German und, Old Norse enn), from PIE *en; cognate with Latin ante, Greek anti (see ante). Phrase and how as an exclamation of emphatic agreement dates from early 1900s.
The second of two items that normally go together (Lunch counter) •''Coffee and'' means ''coffee and doughnuts,'' ''ham and'' means ''ham and eggs,'' etc