We mean those words, but we use them within a fairly narrow frame of reference. (inc.com)
The following car seats are created with narrow frames, and would likely work together in combination to fit three across in most back seats, especially in mid-size vehicles or larger. (mommystroller.com)
The thing that's nice about this tandem stroller is that it has a very narrow frame — similar to those of a single stroller. (mommystroller.com)