There are many English words that you can add an “s” to make it plural. But far fewer words become singular when you add an “s”. What are two examples of these much rarer words?
The moon. The moon has been around for quite some time, but there’s a “new” moon every month or so. A Blue moon is a rare event. The moon is a body of rock, so it’s never empty, but we do see what we call a full moon some nights. And the moon’s gravity “pulls” on the ocean to create low and high tides, but it doesn’t push anyone around because it’s a friendly fellah.
A man is running across a field at night clutching something in his arms as several other men pursue him. He looks back and sees they’re getting closer. In a final burst of effort his pursuers catch up and bring him crashing to the ground. His pursuers stand over him but do not touch him or take what he was carrying. Why not? Who was the running man?
He was born on February 29th in a leap year. Consequently, in his 87 years, he only witnessed twenty-one of his actual birthdays. The other years there was no February 29th.
I am pronounced as one letter but written as three, There are two of me, I am single, I am double, I can be blue, brown, black or green. I can be read from right to left or left to right and am still the same.