What does inch mean?
An inch is a unit of length in the imperial and United States customary systems, equal to one-twelfth of a foot and exactly 2.54 centimetres. The word can also refer informally to a very small distance or amount, as in phrases such as 'every inch' and 'not an inch'. As a verb, inch means to move or change gradually, often with difficulty: someone may inch a door open, inch closer to an agreement, or watch prices inch upward. The verb form conveys caution, reluctance, or slow, incremental progress, while the noun is useful whenever a precise or approximate small measurement is needed. Although the metric system is more common in many countries, inch measurements remain familiar in Britain and the United States, especially in construction, tailoring, consumer products, and informal expressions about distance and change.
A unit of length equal to one-twelfth of a foot or 2.54 centimetres; also, informally, a very small distance or amount.
"The painting was several inches larger than the frame."
To move, advance, or change slowly in small increments.
"The car edged forward and inched into the narrow gap."
The plural of the noun is 'inches'; the 'es' ending restores the final consonant sound.
"The shelf is twelve inches deep."
An inch is exactly one-twelfth of a foot, a division that grew from the Roman system based on twelfths.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does inch come from?
The word comes from Old English ince, meaning a unit of length. That English word was borrowed from Latin uncia, meaning a twelfth part, which also gave English ounce. The English measure was historically associated with the width of a thumb, later standardized to one-twelfth of a foot. The verb meaning 'to move by small increments' developed from the noun's sense of a short distance.
Related word forms
How inch is actually used
The noun is used in both formal and informal contexts. The verb is common in the idioms 'inch closer', 'inch forward', and 'inch up'; in these expressions it often means to progress slowly or cautiously rather than literally by a unit of length.
Easily confused with inch
An inch is a unit of length, whereas an inchworm is a small caterpillar that moves in an inching manner.