What I’ve noticed reading the responses here, is a constant use of the terms non-religious and atheist.
While they are accurate and the details are on point, I find it interesting that much of the discussion is actually about secularism but no one is using that term.
Whatever the reasons for this, I think you are all (I’m assuming mostly Americans) missing a trick here. Secularism is woven into the very fabric of American society and is constantly under attack by the religious (mostly) right, especially in recent years.
As a Brit, we have had to overcome a long history of religious domination and to some extent that continues. The National Secular Society and Humanists UK work tirelessly in this regard.
I would like to see greater use of the term secular in discourse between and from Americans. I honestly believe that language has a huge effect on ourselves as individuals, and constant use of words that are our goals and that have positive connotations are extremely beneficial to us, and by extension our societies.