My mother used to call women who wore too much makeup and smoked on the street "common." She meant "lacking refinement" as in "low class."
"Common" nouns are ordinary ones, not worthy of capitalization, which are called "proper."
The "common" good includes everyone in the community.
"Common" knowledge refers to the stuff everyone knows.
What a weird word common is, ranging widely through ordinary, plain, familiar, popular, and even vulgar implications.
Not one of these meanings describes the uncommon beauty of a brown butterfly, tiny striped fly, and flying caterpillar I stalked for more than an hour under coolly intense sun in the community garden. The Common Buckeye, a True Brushfoot, sports long hair, orange epaulet bars, spotted eyes, orange and buttery stripes, and spots like eyes that glow turquoise on and under the wings.
Nearby, a tiny fly luxuriated in a hot blossom, and a butterfly-in-the-making sunned on flower and leaf, flitting about from light to shade. Despite an extensive Web search, I'm not sure what fly I saw or which "common" butterfly will emerge, but I think I'll go back tomorrow to see what can be see.
Bugs are, after all, "common" in the garden.