A hinge is a type of bearing that connects two solid objects, typically allowing only a limited angle of rotation between them. Two objects connected by an ideal hinge rotate relative to each other about a fixed axis of rotation (the geometrical axis of the hinge). Hinges may be made of flexible material or of moving components.

Ball Bearing Hinges
These Hinges are equipped with ball bearings between the hinge knuckles to reduce friction thus providing a much smoother action compared to an un-washered or non ball bearing hinges. These types of hinges are  designed for heavy duty doors that open to the exterior. They are permanently lubricated.

Butt/Mortise Hinges
These hinges are inset (mortised) into the door and frame. Most residential hinges are made of steel, although mortise hinges for outswing doors are often made of stainless steel base to prevent corrosion.

Continuous Hinges
Continuous Hinges, which run the entire length of the door (also known as "Piano Hinges")

Concealed Hinges
Concealed Hinges used for furniture doors (with or without self-closing feature, and with or without dampening systems). They are made of 2 parts: One part is the hinge cup and the arm; the other part is the mounting plate.

Butterfly or Parliament Hinges
Butterfly or Parliament Hinges. These were known as Dovetail hinges from the 17th century onwards and can be found on old desks and cabinets from about 1670 until the 18th century. The form of these hinges varied slightly between manufacturers, and their size ranged from the very large for heavy doors to the tiniest decorative hinge for use on jewellery caskets. Many hinges of this type were exported to America to support the home trade's limited supply. They are still found to be both fairly cheap and decorative, especially on small items.

H Hinges
H Hinges - Shaped like an H and used on flush mounted doors. Small H hinges (3" to 4") tend to be used for cabinets hinges, while larger hinges (6" to 7") are for passage doors or closet doors.

Rising and Falling Hinges
These types of hinges are used for doors that cannot open or close due to a high carpet or an uneven floor. Rising Hinges when required to raise the door when opening, Falling hinges when the door is required to fall open and lift-off for the purpose of removing the door from the opening without the need to remove the hinges.

Spring Hinges
Spring Hinges contain one or more springs to move the door into a closed position. They may be either singe-or double acting.

Lift-Off Hinges
Lift-off hinges come as two separate leaves - the door leaf and the frame leaf, hence they are handed – left & right. The frame leaf is always the male leaf and the door leaf the female equivalent. Lift-off hinges allow the door to be removed without unscrewing the leaves themselves.

Flush Hinges
This type of hinge does not require a recess to be cut. They are not as strong as butt hinges but can be used for light-weight doors and small box construction.