types:
bar
an obstruction (usually metal) placed at the top of a goal
barrier
a structure or object that impedes free movement
blockade
something that prevents access or progress
obstacle
an obstruction that stands in the way (and must be removed or surmounted or circumvented)
tumbler
a movable obstruction in a lock that must be adjusted to a given position (as by a key) before the bolt can be thrown
barricade
a barrier (usually thrown up hastily) to impede the advance of an enemy
breech closer,
breechblock
a metal block in breech-loading firearms that is withdrawn to insert a cartridge and replaced to close the breech before firing
bulwark
a fencelike structure around a ship's deck (usually plural)
clog
any object that acts as a hindrance or obstruction
crash barrier
a strong protective barrier that is erected around a racetrack or in the middle of a dual-lane highway in order to reduce the likelihood of severe accidents
dam,
dike,
dyke
a barrier constructed to contain the flow of water or to keep out the sea
fender,
wing
a barrier that surrounds the wheels of a vehicle to block splashing water or mud
grate,
grating
a barrier that has parallel or crossed bars blocking a passage but admitting air
hazard
an obstacle on a golf course
hurdle
a light movable barrier that competitors must leap over in certain races
pin,
pin tumbler
cylindrical tumblers consisting of two parts that are held in place by springs; when they are aligned with a key the bolt can be thrown
rail,
railing
a barrier consisting of a horizontal bar and supports
barricade,
roadblock
a barrier set up by police to stop traffic on a street or road in order to catch a fugitive or inspect traffic etc.
speed bump
a hindrance to speeding created by a crosswise ridge in the surface of a roadway
vapor lock,
vapour lock
a stoppage in a pipeline caused by gas bubbles (especially a stoppage that develops in hot weather in an internal-combustion engine when fuel in the gas line boils and forms bubbles that block the flow of gasoline to the carburetor)
water jump
a pool or stream in a steeplechase or similar contest