The riddle
What Has Many Rings but No Fingers?
Two answers, one word
Tree and telephone are the two answers in common use. A tree has rings in its trunk, and a telephone rings when a call comes in. Neither has fingers. Which one a person says first depends on whether "rings" is heard as a shape or as a sound. Both are right, and a bell fits the wording too.
What tree rings record
In a climate with a growing season and a resting season, a tree adds a new layer of wood each year, so counting the rings from the bark to the center gives its age in years. Each ring is a band of lighter wood grown early in the season and a band of darker, denser wood grown late. The pattern is not universal. Trees in the tropics, where growth does not stop for a season, may form more than one ring in a year or none at all, according to tree-ring researchers at the University of Arizona. One ring a year is the usual pattern, not a law.
Why a phone rings
Early telephones had a real bell inside that sounded when a call arrived. People went on saying a phone "rings" long after the bell was replaced by electronic tones, and the verb stuck. Merriam-Webster lists both the bell sense and the telephone sense.
A planet with rings
Saturn also has rings and no fingers. NASA describes them as made of billions of pieces of ice and rock, mostly water ice.