rule of thumb Definition

rule of thumb
noun

1. A method of doing something, based on practical experience rather than theory or careful calculation. Also (rule-of-thumb) as adj.

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thumb
noun

1. In humans: the two-boned digit on the inner side of the hand, set lower than and at a different angle to the other four digits.
2. The part of a glove or mitten that covers this digit.
3. In other animals: the digit corresponding to the human thumb.

verb thumbed, thumbing

tr & intr
1. To turn over the pages of (a book or magazine, etc) to glance at the contents.

Form: thumb through something (often)
2. To smudge or wear something with the thumb.
tr & intr
3. To hitchhike.

Example: I thumbed to London last week
Form: thumb a lift (usually)
Form: thumb a ride

Idiom: all thumbs

Awkward and clumsy.
Thesaurus: clumsy, inept, awkward, maladroit, fumbling, butter-fingered, ham-fisted, ham-handed.

Derivative: rule of thumb

See separate entry.

Idiom: thumb one's nose

To cock a snook (see under snook²).

Idiom: thumbs down

A sign indicating failure, rejection or disapproval.
Thesaurus: rejection, disapproval, rebuff, negation, no, turndown.

Idiom: thumbs up

A sign indicating success, best wishes for success, satisfaction or approval.
Thesaurus: acceptance, approval, encouragement, go-ahead, affirmation, OK, yes, sanction.

Idiom: under someone's thumb

Completely controlled or dominated by them.
Thesaurus: under someone's control, controlled, governed, managed, dominated, supervised.

Etymology: Anglo-Saxon thuma.