- A pair of small wheels attached on either side of the rear wheel of a child's bicycle so that the bicycle is easier for the child to learn to ride.
- (figuratively, sometimes singular as training wheel) Anything designed to make something easier for a novice.
- 2019 August 14, A. A. Dowd, “Good Boys puts a tween spin on the R-rated teen comedy, to mostly funny effect”, in The A.V. Club:
- Yet as with Booksmart, the summer’s earlier riff on that Apatovian classic, there are times when Good Boys feels a little too nice to actually be uproarious. In more ways than one, it’s the training wheels for a better comedy—a slightly edgier and funnier one.
- (wheels on a bicycle): stabilisers (UK)
pair of small wheels attached to a child's bicycle