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clearance

KLEER-uhns /ˈklɪərəns/

nounB2TOEFLIELTS

generalprofessional

The physical space or distance allowed for safe passage, movement, or fit between two objects.

In ergonomics, it represents the minimum physical space required to accommodate the largest users (e.g., ensuring a tall person's legs fit under a desk).

The story behind the word. Formed from the verb 'clear' with the suffix '-ance' in the 16th century, the word originally meant 'the act of clearing away.' By the 18th century, it came to denote the physical space left free between two objects, a concept vital to mechanical engineering and architecture.

Word relationships

headroom: Headroom specifically refers to vertical clearance above a person's head, while clearance can refer to any physical gap in any direction.

obstruction: An obstruction is a physical barrier that blocks passage, whereas clearance is the open space that allows it.

Commonly confused with

tolerance: Tolerance is the allowable variation in a physical measurement during manufacturing, while clearance is the intentional gap designed between two parts.

Word family

clear (verb): Pass by or over without touching.

Collocations

knee clearance
ground clearance
minimum clearance
safety clearance

Example sentences

"The desk design must provide sufficient knee clearance for users in the ninety-fifth percentile of height." Workspace design

Memory hook

Clearance is the space needed to keep things 'clear' of each other so they don't crash or rub. Clearance = Clear space.

When not to use

Do not confuse with 'clearance' in a retail context (selling off old stock cheaply) or security context (permission to access secret info), though they share the same root.

Fun facts

The standard clearance for public doorways in many countries is 32 inches (81 cm) of clear width to ensure wheelchair accessibility.