An editing colleague from Wisconsin offered a memorable way to divide the similar words continuous and continual.
There’s “engaged in continuous sex” and “engaged in continual sex,” she said in a tweet.
There is a difference, more noticeable with some subjects than others.
Word forms sometimes spring up separately, sometimes with subtle differences that people either accept or that are lost by what some would call misuse. These two words overlap quite often, but there are usage tendencies that are useful to clarity.
Continuous and continual share the Latin root continere, which means to hang together, to hold together, or to contain. Continual first appears in about 1340 in the Prose Treatise of Richard Rolle, according to the Oxford English Dictionary. Continuous followed 300 years later.
The subtle difference between these two might be easy to ignore. For an ongoing period of time, continuous or continual both are widely used and accepted.
For a period of time that includes the occasional break, continual alone suggests starting and stopping. It’s rarely used in a physical sense—we’d say “continuous fence,” for example. In the continuous sex vs. continual sex example, continual seem the more likely choice for an honest writer or a careful editor.
By the way, spellcheck won’t help you if you forget the second u in continuous. A continuo is an accompanying part, often a piano, with a base line in a piece of music; the plural is continuos. The Latin root is the same.
