It is an idiom meaning to come in for a visit. It implies that Johnny was going somewhere else and on the way dropped in on Mechelle and her family. Won't you come by my house sometime?
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
perspolisCan I use "came" instead of "came by"?No, you can't. The sentence is written in the simple past tense, and all of the activities it refers to are past activities. The simple past tense of the verb "come" is "came".