Continuous and Continual

I remember being taught the difference between continuous and continual at school and knowing that they were not interchangeable, but also knowing that I’d be likely to muddle them up. So I decided to look them up fifty years later and be clear about how to distinguish between them.

I discovered that both adjectives describe duration:

Continuous indicates duration from a point in time to another point in time without stopping or interruption:

• The continuous noisy humming of the cicadas in the jungle got on his nerves.
• He suffered a continuous bout of illness lasting for three months.

Continual indicates duration that goes on over a long period of time, recurring at regular or frequent intervals, but with breaks in between.

• The continual street repairs by various companies disrupted traffic for months.
• To be a successful ballet dancer requires continual practice.

The adverbs continuously and continually have the same distinction:

• The company have continuously sought to improve conditions and procedures.
• She is continually making long international telephone calls which she does not pay for.