how are you?

1. A conventional greeting to an acquaintance
2. Sometimes specifically referring to his or her state of health

how come? (informal)

How does that come about?

how-do-you-do see under do¹; see also howdy

how now?

1. What is this?
2. Why is this so?

how so? (archaic)

How can this be so?, why?

how's that /how-zatˈ/ (cricket; sometimes written howzatˈ)

The appeal of the fielding side to the umpire to give the batsman out

how's your father (facetious)

1. Amorous frolicking
2. Sexual intercourse
3. Nonsense, foolish activity

the how and the why

The manner and the cause