Legally, the IRS does not distinguish between a “gig worker” and a typical independent contractor or freelancer. Any worker that is not technically an employee of a business is expected to act as a 1099 self-employed contractor unless they have registered their business as a separate entity.
Culturally, a “gig” worker is the name for someone who typically accepts jobs on a very short-term basis with no expectation of a long term relationship. They often work for cash on an as-needed basis, unlike freelancers who may maintain relationships for a longer period.
Increasingly, gig workers benefit from businesses that provide a platform for them to view available work, accept it, and perform that work all on their preferred schedule. Uber, GrubHub, and Instacart are three examples of such businesses, although there is some debate about whether this relationship actually qualifies as a “gig” or employee relationship.
In sum: all gig workers are independent contractors when properly classified, but gig workers have a reputation for on-again, off-again work via an informal relationship with the business offering the work.