13-letter words containing o, b, s, t, r, u
- transboundary — something that indicates bounds or limits; a limiting or bounding line.
- treasury bond — any of various interest-bearing bonds issued by the U.S. Treasury Department, usually maturing over a long period of time.
- truck bolster — the upper transverse member of a car truck that holds the truck center plate and receives the car's weight.
- tuberous root — a true root so thickened as to resemble a tuber, but bearing no buds or eyes.
- tubuliflorous — having the corolla tubular in all the perfect flowers of a head, as certain composite plants.
- unobstructive — to block or close up with an obstacle; make difficult to pass: Debris obstructed the road.
- unobtrusively — not obtrusive; inconspicuous, unassertive, or reticent.
- unsmotherable — unquenchable
- unsupportable — capable of being supported; endurable; maintainable.
- vitreous body — a transparent gelatinous substance, permeated by fine fibrils, that fills the interior of the eyeball between the lens and the retina
- water-soluble — capable of dissolving in water.