The following terms define Building & Machine Parts
backstay: supporting or checking piece in mechanism, esp. anchored tension member that supports compression member.
baffle: obstructing member, esp. used to hold back or turn aside flow of gas or liquid.
bail: supporting half hoop; hinged bar that holds paper to platen in typewriter.
ball-and-socket joint: joint between rods or links in which ball-like termination fits into concave, spherical socket.
baluster: small vertical member connecting stair tread & handrail.
band: ring or encircling strip, used esp. to bind something.
bar: straight supporting to.
barb: sharp, hooked projection.
barb & shaft: point & length of weapon, missile, or tool.
base: bottommost component on which structure rests.
baseboard: finished interior trim where wall meets floor.
baseplate: steel plate at bottom of steel column.
baseshoe: molding placed against baseboard at floor.
batten: narrow wood strip that covers seam between boards.
batter boards: horizontal crosspieces nailed to posts in ground at corners of excavation to locate corners & establish level.
beam: horizontal structural member of wood or steel, used to support load.
beam pocket: notch that holds supporting beam.
bearing: sliding or turning machine part point of support.
bearing pile: column sunk into ground or foundation to support vertical load.
bearing wall: wall that supports a floor or roof & walls above it.
becket: looped rope with large hook & eye, used to secure loose ropes & spars.
bed: horizontal layer of masonry mortar that holds bricks.
berm: narrow dirt ledge that supports beams.
bilge: point of largest circumference of cask or barrel.
bit: cutting or drilling part of tool.
block: enclosure for pulley; mold; building unit.
boom: projecting beam, spar, or supporting arm.
boss: raised knob on flat surface.
box beam: hollow structural member that supports loads.
brace: connecting or reinforcing element, usually of wood.
bracket: projecting support fixture.
brake: machine element used to stop motion.
breather: vent, as in machine covering or storage tank used to equalize pressure or permit entry or escape of vapor .
bridging: rows of small diagonal braces nailed between ceiling joists to support floor weight.
bristle: stiff hair, filament.
building block: component or part of structure.
building material: substance from which something is made or constructed.
built-ins: furniture & other nonstructural elements permanently incorporated in building.
built-up beam: support made of several smaller beams joined together.
bulkhead: partition; retaining wall.
bulwark: fortified wall or rampart.
bumper: shock-absorbing element.
bung: stopper in opening or spout of cask.
butt: thick end of something.
button: small, pressable control knob.
buttress: projecting support structure.
bypass: auxiliary pipe or channel connected to main passage, used to conduct gas or liquid around pipe or fixture.