By BILL EDWARDS

In the 1970s Mounds and Almond Joy candy bars were advertised with the phrase: “Sometimes you feel like a nut, Sometimes You Don’t, Almond Joy’s got nuts, Mounds don’t.” While they did not share almonds, both Almond Joy and Mounds did share such “nut” sources as shredded coconut and chocolate. Undermining the jingle is that almonds are not true nuts, and, in fact, there are no true nut components in either candy bar.

Almonds, coconut, and chocolate are better labeled as “culinary nuts” and botanically all are referred to as “drupes” — a fleshy fruit with thin skin and a central stone containing the seed, such as a plum, cherry, almond, or olive. A true nut is classified by botanists as a type of fruit comprised of a shell and a seed.

While a coconut and an almond have a hard shell and a seed, true nuts (such as acorns, chestnuts, and hazelnuts) are indehiscent — they don’t split open to release their seeds when ripe. In the case of the coconut and the almond, the seed germinates and then sprouts from the end of the shell, which eventually splits (dehisces) the shell exposing the seed.

So why is one of the few botanical nuts of North America much more frequently called an “acorn” instead of the much less used term “oaknut?” The etymology is a little complex, which is often true for words that have derivations from many different countries and are used to identify something that has a highly varied and significant economic role for humans and major ecological impact.

A search for the origins of the word “acorn” produces many conflicting, and somewhat esoteric, analyses. My interpretation is that “acorn” is a compound word consisting of “ac/ak” which refers to either the oak/beech tree, or the open land where these trees grow, and “corn” which refers to “mast” or the fruit of the trees.

For a view of the songs and loopy TV ads of the 1970s, go to Google and use the search term “sometimes you feel like a nut”. Click on “view all” under the Images link. Be prepared to waste a lot of time.

— Bill Edwards is a trail guide at Mission Trails Regional Park.