In engineering, a stringer is a small, subsidiary beam, joist, or girder. A stringer is connected with, and supported by, other portions of a structure, such as a roof-rafter, floor joist, or the girders or beams of a bridge carrying the rails or roadway and supported in turn by other girders. Research Stringer
In architecture a gain is a square or bevelled notch cut out of a girder, binding joist, or other timber which supports a floor beam, so as to receive the end of the floor beam.
In architecture a joist is a piece of timber laid horizontally, or nearly so, to which the planks of the floor, or the laths or furring strips of a ceiling, are nailed. The joints are called varying names according to their position or use, a binding joist, bridging joist, ceiling joist, trimming
joist, etc. Research Joist