Flanged railway wheel. A flange is an external or internal ridge, or rim (lip), for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera; or for a flange of a rail car or tram wheel.
noun, plural subtleties. 1. the state or quality of being subtle. 2. delicacy or nicety of character or meaning. 3. acuteness or penetration of mind; delicacy of discrimination. 4. a fine-drawn distinction; refinement of reasoning: the subtleties of logic.
adjective, subtler, subtlest. 1. thin, tenuous, or rarefied, as a fluid or an odor. 2. fine or delicate in meaning or intent; difficult to perceive or understand: subtle irony. 3. delicate or faint and mysterious: a subtle smile.