gig economy
noun phrase

- a way of working that is based on people having temporary jobs or doing separate pieces of work, each paid separately, rather than working for an employer

Cambridge Dictionary

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ORIGIN

First appearing (in this context) around 1926, the word gig has referred to a single performance by a musician or group of musicians, especially playing non-classical music.

It's easy to see how gig has now become an adjective describing the growing phenomenon of task-based employment. Rather than working under a contract of employment and receiving regular salaries, workers receive one-off payments for the individual tasks, aka the 'gigs', they do.

You may also sometimes come across alternative (and much earlier) meanings of gig. These are both related to transport:

gig = a light, two-wheeled carriage pulled by one horse

gig = a light, fast, narrow boat adapted for rowing or sailing